Publications by authors named "Luis F Callado"

97 Publications

α- and α-adrenoceptor expression and functionality in postmortem prefrontal cortex of schizophrenia subjects.

Eur Neuropsychopharmacol 2021 Jun 19;52:3-11. Epub 2021 Jun 19.

Department of Pharmacology, University of the Basque Country, UPV/EHU, Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain; Biocruces Bizkaia Health Research Institute, Barakaldo, Bizkaia, Spain. Electronic address:

Previous evidence suggests that α-adrenoceptors (α-AR) may be involved in the pathophysiology of schizophrenia. However, postmortem brain studies on α-AR expression and functionality in schizophrenia are scarce. The aim of our work was to evaluate α-AR and α-AR expression in different subcellular fractions of prefrontal cortex postmortem tissue from antipsychotic-free (absence of antipsychotics in blood at the time of death) (n = 12) and antipsychotic-treated (n = 12) subjects with schizophrenia, and matched controls (n = 24). Functional coupling of α-AR to G proteins induced by the agonist UK14304 was also tested. Additionally, G protein expression was also evaluated. In antipsychotic-free schizophrenia subjects, α-AR and α-AR protein expression was similar to controls in all the subcellular fractions. Conversely, in antipsychotic-treated schizophrenia subjects, increased α-AR expression was found in synaptosomal plasma membrane and postsynaptic density (PSD) fractions (+60% and +79% vs controls, respectively) with no significant changes in α-AR. [S]GTPγS SPA experiments showed a significant lower stimulation of G and G proteins by UK14304 in antipsychotic-treated schizophrenia subjects, whereas stimulation in antipsychotic-free schizophrenia subjects remained unchanged. G protein stimulation was significantly decreased in both antipsychotic-free and antipsychotic-treated schizophrenia subjects compared to controls. Expression of G protein did not differ between groups, whereas G levels were increased in PSD of schizophrenia subjects, both antipsychotic-free and antipsychotic-treated. G protein expression was increased in PSD of antipsychotic-treated subjects and in the presynaptic fraction of antipsychotic-free schizophrenia subjects. The present results suggest that antipsychotic treatment is able to modify in opposite directions both the protein expression and the functionality of α-AR in the cortex of schizophrenia patients.
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http://dx.doi.org/10.1016/j.euroneuro.2021.05.012DOI Listing
June 2021

Characterization of dopamine D receptor coupling to G proteins in postmortem brain of subjects with schizophrenia.

Pharmacol Rep 2021 Jul 1. Epub 2021 Jul 1.

Department of Pharmacology, University of the Basque Country UPV/EHU, 48940, Leioa, Bizkaia, Spain.

Background: Alterations of dopamine D (D1R) and D receptor (D2R) are proposed in schizophrenia but brain neuroimaging and postmortem studies have shown controversial results in relation to D1R and D2R density. Besides, scarce information on the functionality of brain D1R and D2R is available. The present study characterized G-protein activation by D1R and D2R agonists in postmortem human brain. Furthermore, D2R functional status was compared between schizophrenia and control subjects.

Methods: G-protein receptor coupling was assessed in control caudate nucleus and frontal cortex by [S]GTPγS-binding stimulation induced by increasing concentrations (10-10 M) of dopamine, and the selective dopaminergic agonists SKF38393 (D1R) and NPA (D2R). Concentration-response curves to NPA stimulation of [S]GTPγS binding were analyzed in antipsychotic-free (n = 10) and antipsychotic-treated (n = 7) schizophrenia subjects and matched controls (n = 17).

Results: In caudate, [S]GTPγS-binding responses to agonists were compatible with the existence of functional D2R. In contrast, stimulations in cortex showed responses that did not correspond to D1R or D2R. [S]GTPγS-binding activation by NPA in caudate displayed biphasic curves with similar profile in schizophrenia (EC = 7.94 nM; EC = 7.08 μM) and control (EC = 7.24 nM; EC = 15.14 μM) subjects. The presence or absence of antipsychotic medication did not influence the pharmacological parameters.

Conclusions: Feasibility of functional evaluation of dopamine receptors in postmortem human brain by conventional [S]GTPγS-binding assays appears to be restricted to signalling through inhibitory G proteins. These findings provide functional information about brain D2R status in subjects with schizophrenia and do not support the existence of D2R supersensitive in this mental disorder.
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http://dx.doi.org/10.1007/s43440-021-00305-4DOI Listing
July 2021

Benzofuranyl-2-imidazoles as imidazoline I receptor ligands for Alzheimer's disease.

Eur J Med Chem 2021 May 20;222:113540. Epub 2021 May 20.

Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, E-08028, Barcelona, Spain. Electronic address:

Recent findings unveil the pharmacological modulation of imidazoline I receptors (I-IR) as a novel strategy to face unmet medical neurodegenerative diseases. In this work, we report the chemical characterization, three-dimensional quantitative structure-activity relationship (3D-QSAR) and ADMET in silico of a family of benzofuranyl-2-imidazoles that exhibit affinity against human brain I-IR and most of them have been predicted to be brain permeable. Acute treatment in mice with 2-(2-benzofuranyl)-2-imidazole, known as LSL60101 (garsevil), showed non-warning properties in the ADMET studies and an optimal pharmacokinetic profile. Moreover, LSL60101 induced hypothermia in mice while decreased pro-apoptotic FADD protein in the hippocampus. In vivo studies in the familial Alzheimer's disease 5xFAD murine model with the representative compound, revealed significant decreases in the protein expression levels of antioxidant enzymes superoxide dismutase and glutathione peroxidase in hippocampus. Overall, LSL60101 plays a neuroprotective role by reducing apoptosis and modulating oxidative stress.
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http://dx.doi.org/10.1016/j.ejmech.2021.113540DOI Listing
May 2021

Characterization of Hevin (SPARCL1) Immunoreactivity in Postmortem Human Brain Homogenates.

Neuroscience 2021 07 24;467:91-109. Epub 2021 May 24.

Department of Pharmacology, University of the Basque Country, UPV/EHU, Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain. Electronic address:

Hevin is a matricellular glycoprotein that plays important roles in neural developmental processes such as neuronal migration, synaptogenesis and synaptic plasticity. In contrast to other matricellular proteins whose expression decreases when development is complete, hevin remains highly expressed, suggesting its involvement in adult brain function. In vitro studies have shown that hevin can have different post-translational modifications. However, the glycosylation pattern of hevin in the human brain remains unknown, as well as its relative distribution and localization. The present study provides the first thorough characterization of hevin protein expression by Western blot in postmortem adult human brain. Our results demonstrated two major specific immunoreactive bands for hevin: an intense band migrating around 130 kDa, and a band migrating around 100 kDa. Biochemical assays revealed that both hevin bands have a different glycosylation pattern. Subcellular fractionation showed greater expression in membrane-enriched fraction than in cytosolic preparation, and a higher expression in prefrontal cortex (PFC) compared to hippocampus (HIP), caudate nucleus (CAU) and cerebellum (CB). We confirmed that a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS4) and matrixmetalloproteinase 3 (MMP-3) proteases digestion led to an intense double band with similar molecular weight to that described as SPARC-like fragment (SLF). Finally, hevin immunoreactivity was also detected in human astrocytoma, meningioma, cerebrospinal fluid and serum samples, but was absent from any blood cell type.
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http://dx.doi.org/10.1016/j.neuroscience.2021.05.017DOI Listing
July 2021

Opposite alterations of 5-HT receptor brain density in subjects with schizophrenia: relevance of radiotracers pharmacological profile.

Transl Psychiatry 2021 05 20;11(1):302. Epub 2021 May 20.

Department of Pharmacology, University of the Basque Country, Leioa, Bizkaia, Spain.

The status of serotonin 5-HT receptors (5-HTRs) in schizophrenia has been controversial. In vivo positron emission tomography neuroimaging and in vitro post-mortem binding studies have reported conflicting results about 5-HTR density. Radiotracers bind different receptor conformations depending on their agonist, antagonist or inverse agonist properties. This study investigates 5-HTR density in the post-mortem prefrontal cortex from subjects with schizophrenia and controls using three radiotracers with a different pharmacological profile. The specific binding parameters of the inverse agonist [F]altanserin, the agonist [H]lysergic acid diethylamide (LSD) and the antagonist [H]MDL100907 to brain cortex membranes from 20 subjects with schizophrenia and 20 individually matched controls were evaluated under similar methodological conditions. Ten schizophrenia subjects were antipsychotic-free at death. Saturation curve analyses were performed by non-linear regression to obtain a maximal density of binding sites (B) and the affinity of the respective radiotracers (K). In schizophrenia subjects, 5-HTR density was decreased when quantified by [F]altanserin binding, whereas increased when evaluated by [H]LSD binding. However, [H]MDL100907 binding was unaltered. A slight loss of affinity (higher K) was observed exclusively in [H]LSD binding. The findings were more evident in antipsychotic-free subjects than in antipsychotic-treated subjects. In conclusion, a higher proportion of the 5-HTR-active functional conformation, which is rather identified by agonist radiotracers, was observed in schizophrenia patients. A consequent reduction of the inactive 5-HTR conformation, which is preferentially identified by inverse agonist radiotracers, was also obtained. Antagonist radiotracers do not distinguish between molecular conformations of the receptor, and accordingly, the absence of changes was shown. These results are compatible with the proposed increased functional activity of brain cortical 5-HTRs in schizophrenia.
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http://dx.doi.org/10.1038/s41398-021-01430-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8137947PMC
May 2021

5-HT receptor- and M muscarinic acetylcholine receptor-mediated activation of Gα in postmortem dorsolateral prefrontal cortex of opiate addicts.

Pharmacol Rep 2021 Apr 9. Epub 2021 Apr 9.

Laboratory of Neuropharmacology, IUNICS/IdISPa, University of the Balearic Islands (UIB), Palma de Mallorca, Spain.

Background: Chronic exposure to opiates causes the development of tolerance and physical dependence as well as persistent brain neuroplasticity. Despite a wealth of postmortem human studies for opiate addicts, little direct information regarding the functional status of serotonergic and cholinergic receptor-mediated signaling pathways in the human brain of opiate addicts is yet available.

Methods: Functional activation of Gα proteins coupled to 5-HT and M type muscarinic acetylcholine receptor (mAChR) was assessed by using the method named [S]GTPγS binding/immunoprecipitation in frontal cortical membrane preparations from postmortem human brains obtained from opiate addicts and matched controls.

Results: Concentration-response curves for 5-HT and carbachol in individual subjects were analyzed according to a nonlinear regression model, which generated the values of maximum percent increase (%E), negative logarithm of the half-maximal effect (pEC) and slope factor. As for 5-HT receptor-mediated Gα activation, the %E values were reduced significantly and the pEC values were decreased significantly in opiate addicts as compared to the control group. Regarding carbachol-induced Gα activation, no significant difference in %E or pEC values was detected between the both groups, whereas the slope factor was increased significantly in opiate addicts as compared to the control group.

Conclusion: Our data demonstrate that the signaling pathways mediated by Gα proteins coupled with 5-HT receptors and M mAChRs in prefrontal cortex are functionally altered in opiate addicts in comparison with control subjects. These alterations may underpin some aspects of addictive behavior to opiate as well as neuropsychological consequences or comorbid mental disorders associated with opioid use.
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http://dx.doi.org/10.1007/s43440-021-00248-wDOI Listing
April 2021

Subcellular specificity of cannabinoid effects in striatonigral circuits.

Neuron 2021 05 25;109(9):1513-1526.e11. Epub 2021 Mar 25.

INSERM, U1215 NeuroCentre Magendie, Endocannabinoids and Neuroadaptation, Bordeaux, France; University of Bordeaux, Bordeaux, France.

Recent advances in neuroscience have positioned brain circuits as key units in controlling behavior, implying that their positive or negative modulation necessarily leads to specific behavioral outcomes. However, emerging evidence suggests that the activation or inhibition of specific brain circuits can actually produce multimodal behavioral outcomes. This study shows that activation of a receptor at different subcellular locations in the same neuronal circuit can determine distinct behaviors. Pharmacological activation of type 1 cannabinoid (CB) receptors in the striatonigral circuit elicits both antinociception and catalepsy in mice. The decrease in nociception depends on the activation of plasma membrane-residing CB receptors (pmCB), leading to the inhibition of cytosolic PKA activity and substance P release. By contrast, mitochondrial-associated CB receptors (mtCB) located at the same terminals mediate cannabinoid-induced catalepsy through the decrease in intra-mitochondrial PKA-dependent cellular respiration and synaptic transmission. Thus, subcellular-specific CB receptor signaling within striatonigral circuits determines multimodal control of behavior.
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http://dx.doi.org/10.1016/j.neuron.2021.03.007DOI Listing
May 2021

Spinophilin expression in postmortem prefrontal cortex of schizophrenic subjects: Effects of antipsychotic treatment.

Eur Neuropsychopharmacol 2021 Jan 27;42:12-21. Epub 2020 Nov 27.

Department of Pharmacology, University of the Basque Country, UPV/EHU, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain. Electronic address:

Schizophrenia has been associated with alterations in neurotransmission and synaptic dysfunction. Spinophilin is a multifunctional scaffold protein that modulates excitatory synaptic transmission and dendritic spine morphology. Spinophilin can also directly interact with and regulate several receptors for neurotransmitters, such as dopamine D receptors, which play a role in the pathophysiology of schizophrenia and are targets of antipsychotics. Several studies have thus suggested an implication of spinophilin in schizophrenia. In the present study spinophilin protein expression was determined by western blot in the postmortem dorsolateral prefrontal cortex of 24 subjects with schizophrenia (12 antipsychotic-free and 12 antipsychotic-treated subjects) and 24 matched controls. Experiments were performed in synaptosomal membranes (SPM) and in postsynaptic density fractions (PSD). As previously reported, two specific bands for this protein were observed: an upper 120-130 kDa band and a lower 80-95 kDa band. The spinophilin lower band showed a significant decrease in schizophrenia subjects compared to matched controls, both in SPM and PSD fractions (-15%, p = 0.007 and -15%, p = 0.039, respectively). When schizophrenia subjects were divided by the presence or absence of antipsychotics in blood at death, the lower band showed a significant decrease in antipsychotic-treated schizophrenia subjects (-24%, p = 0.003 for SPM and -26%, p = 0.014 for PSD), but not in antipsychotic-free subjects, compared to their matched controls. These results suggest that antipsychotics could produce alterations in spinophilin expression that do not seem to be related to schizophrenia per se. These changes may underlie some of the side effects of antipsychotics.
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http://dx.doi.org/10.1016/j.euroneuro.2020.11.011DOI Listing
January 2021

Di-aryl guanidinium derivatives: Towards improved α2-Adrenergic affinity and antagonist activity.

Eur J Med Chem 2021 Jan 24;209:112947. Epub 2020 Oct 24.

School of Chemistry, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160, Pearse Street, Dublin 2, Ireland. Electronic address:

Compounds with excellent receptor engagement displaying α-AR antagonist activity are useful not only for therapeutic purposes (e.g. antidepressants), but also to help in the crystallization of this particular GPCR. Therefore, based on our broad experience in the topic, we have prepared eighteen di-aryl (phenyl and/or pyridin-2-yl) mono- or di-substituted guanidines and 2-aminoimidazolines. The in vitro α-AR binding affinity experiments in human brain tissue showed the advantage of a 2-aminoimidazolinium cation, a di-arylmethylene core, a conformationally locked pyridin-2-yl-guanidine and a di-substituted guanidinium to achieve good α-AR engagement. After different in vitro [S]GTPγS binding experiments in human prefrontal cortex tissue, it was possible to identify that compounds 7a, 7b and 7c were α-AR partial agonist, whereas 8h was a potent α-AR antagonist. Docking and MD studies with a model of α-AR and two crystal structures suggest that antagonism is achieved by compounds carrying a di-substituted guanidine which substituent occupy a pocket adjacent to TM5 without engaging S200 or S204, and a mono-substituted cationic group, which favorably interacts with E94.
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http://dx.doi.org/10.1016/j.ejmech.2020.112947DOI Listing
January 2021

5-HT receptor-mediated Gα activation in psychiatric disorders: A postmortem study.

World J Biol Psychiatry 2020 Nov 9:1-11. Epub 2020 Nov 9.

Laboratory of Neuropharmacology, IUNICS/IdISPa, University of the Balearic Islands (UIB), Palma de Mallorca, Spain.

Objectives: Serotonin-2A (5-HT) receptors play an important role in the regulation of many brain functions that are disturbed in patients with such psychiatric diseases as mood disorders and schizophrenia. The objective of this study was to evaluate 5-HT receptor-mediated signalling pathway through Gα activation in psychiatric patients by using post-mortem brain samples.

Methods: Functional activation of Gα proteins coupled to 5-HT receptors was determined by means of [S]GTPγS binding/immunoprecipitation assay in post-mortem prefrontal cortex of psychiatric patients diagnosed as bipolar disorder (BP), major depressive disorder (MDD), and schizophrenia, and individually matched controls. The effects of antipsychotic treatment as well as suicide were also analysed.

Results: There was no significant difference in maximum percent increase (%E) or slope factor among the four groups. The negative logarithm of concentration eliciting the half-maximal effect (pEC) was significantly reduced in BP and schizophrenia patients as compared to controls. These alterations were attributable to antipsychotic medication. The pEC values in 'non-suicide' group of schizophrenia, but not in 'suicide' group, were significantly reduced as compared with controls.

Conclusions: Altered 5-HT receptor-mediated signalling pathway through Gα proteins in prefrontal cortex might be apparently involved in pathophysiology and pharmacotherapy of BP and schizophrenia. In schizophrenic patients, these alterations as a result of successful treatment with antipsychotic agents may help in prevention of suicidal behaviour.
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http://dx.doi.org/10.1080/15622975.2020.1839967DOI Listing
November 2020

Decreased striatal adenosine A-dopamine D receptor heteromerization in schizophrenia.

Neuropsychopharmacology 2021 02 3;46(3):665-672. Epub 2020 Oct 3.

Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, UB, L'Hospitalet de Llobregat, Barcelona, Spain.

According to the adenosine hypothesis of schizophrenia, the classically associated hyperdopaminergic state may be secondary to a loss of function of the adenosinergic system. Such a hypoadenosinergic state might either be due to a reduction of the extracellular levels of adenosine or alterations in the density of adenosine A receptors (ARs) or their degree of functional heteromerization with dopamine D receptors (DR). In the present study, we provide preclinical and clinical evidences for this latter mechanism. Two animal models for the study of schizophrenia endophenotypes, namely the phencyclidine (PCP) mouse model and the AR knockout mice, were used to establish correlations between behavioural and molecular studies. In addition, a new AlphaLISA-based method was implemented to detect native AR-DR heteromers in mouse and human brain. First, we observed a reduction of prepulse inhibition in AR knockout mice, similar to that observed in the PCP animal model of sensory gating impairment of schizophrenia, as well as a significant upregulation of striatal DR without changes in AR expression in PCP-treated animals. In addition, PCP-treated animals showed a significant reduction of striatal AR-DR heteromers, as demonstrated by the AlphaLISA-based method. A significant and pronounced reduction of AR-DR heteromers was next demonstrated in postmortem caudate nucleus from schizophrenic subjects, even though both DR and AR were upregulated. Finally, in PCP-treated animals, sub-chronic administration of haloperidol or clozapine counteracted the reduction of striatal AR-DR heteromers. The degree of AR-DR heteromer formation in schizophrenia might constitute a hallmark of the illness, which indeed should be further studied to establish possible correlations with chronic antipsychotic treatments.
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http://dx.doi.org/10.1038/s41386-020-00872-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8027896PMC
February 2021

Fundamental features of receptor-mediated Gα activation in human prefrontal cortical membranes: A postmortem study.

Brain Res 2020 11 1;1747:147032. Epub 2020 Aug 1.

Laboratory of Neuropharmacology, Institut Universitari d'Investigació en Ciències de la Salut (IUNICS), University of the Balearic Islands (UIB), and Institut d'investigació Sanitària Illes Balears (IdISBa), Palma de Mallorca, Spain.

To elucidate possible abnormalities in transmembrane signal transduction in psychiatric diseases, use of autopsy brain is a feasible approach. However, postmortem studies should be interpreted with caution concerning such factors as age, gender, psychotropic drug history, agonal state, postmortem delay (PMD), and storage period. In this study, agonist-induced [S]GTPγS binding was performed in postmortem dorsolateral prefrontal cortical membranes of 40 control subjects. In addition to the previously reported G protein-coupled receptor (GPCR)-mediated G activation, κ-opioid receptor-mediated [S]GTPγS binding was detected by using U-50,448. The responses elicited by 16 different agonists were determined, and the effects of several factors were investigated. Gender difference was negligible. Concentration-response curve of histamine H receptor-mediated [S]GTPγS binding was shifted rightward in the subjects with some drugs detected at toxicological screening. Age-related alterations were minimal, except for the age-dependent supersensitivity of μ-opioid receptor-mediated Gα activation, revealed by endomorphin-1- and DAMGO-stimulated [S]GTPγS binding. Age-related increase in %E values was also detected as to DPDPE-induced [S]GTPγS binding through δ-opioid receptors. With an exception of NOP receptor/G-protein coupling, GPCR-mediated [S]GTPγS binding is relatively stable irrespective of PMD or storage period. There were many positive correlations among the %E values for different receptor subtypes, which might reflect formation of heterodimer complex of such GPCRs coupled to the same G proteins. These results provide us with important fundamental data in the future project using human postmortem brains from patients with psychiatric disorders.
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http://dx.doi.org/10.1016/j.brainres.2020.147032DOI Listing
November 2020

Sex-dependent pharmacological profiles of the synthetic cannabinoid MMB-Fubinaca.

Addict Biol 2021 05 3;26(3):e12940. Epub 2020 Aug 3.

INSERM, U1215 NeuroCentre Magendie, Bordeaux, France.

Synthetic cannabinoids have emerged as novel psychoactive substances with damaging consequences for public health. They exhibit high affinity at the cannabinoid type-1 (CB ) receptor and produce similar and often more potent effects as other CB receptor agonists. However, we are still far from a complete pharmacological understanding of these compounds. In this study, by using behavioral, molecular, pharmacological, and electrophysiological approaches, we aimed at characterizing several in vitro and in vivo pharmacological effects of the synthetic cannabinoid MMB-Fubinaca (also known as AMB-Fubinaca or FUB-AMB), a particular synthetic cannabinoid. MMB-Fubinaca stimulates CB receptor-mediated functional coupling to G-proteins in mouse and human brain preparations in a similar manner as the CB receptor agonist WIN55,512-2 but with a much greater potency. Both drugs similarly activate the CB receptor-dependent extracellular signal-regulated kinase (ERK) pathway. Notably, in vivo administration of MMB-Fubinaca in mice induced greater behavioral and electrophysiological effects in male than in female mice in a CB receptor-dependent manner. Overall, these data provide a solid pharmacological profiling of the effects of MMB-Fubinaca and important information about the mechanisms of action underlying its harmful impact in humans. At the same time, they reinforce the significant sexual dimorphism of cannabinoid actions, which will have to be taken into account in future animal and clinical studies.
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http://dx.doi.org/10.1111/adb.12940DOI Listing
May 2021

Sex-dependent pharmacological profiles of the synthetic cannabinoid MMB-Fubinaca.

Addict Biol 2021 05 3;26(3):e12940. Epub 2020 Aug 3.

INSERM, U1215 NeuroCentre Magendie, Bordeaux, France.

Synthetic cannabinoids have emerged as novel psychoactive substances with damaging consequences for public health. They exhibit high affinity at the cannabinoid type-1 (CB ) receptor and produce similar and often more potent effects as other CB receptor agonists. However, we are still far from a complete pharmacological understanding of these compounds. In this study, by using behavioral, molecular, pharmacological, and electrophysiological approaches, we aimed at characterizing several in vitro and in vivo pharmacological effects of the synthetic cannabinoid MMB-Fubinaca (also known as AMB-Fubinaca or FUB-AMB), a particular synthetic cannabinoid. MMB-Fubinaca stimulates CB receptor-mediated functional coupling to G-proteins in mouse and human brain preparations in a similar manner as the CB receptor agonist WIN55,512-2 but with a much greater potency. Both drugs similarly activate the CB receptor-dependent extracellular signal-regulated kinase (ERK) pathway. Notably, in vivo administration of MMB-Fubinaca in mice induced greater behavioral and electrophysiological effects in male than in female mice in a CB receptor-dependent manner. Overall, these data provide a solid pharmacological profiling of the effects of MMB-Fubinaca and important information about the mechanisms of action underlying its harmful impact in humans. At the same time, they reinforce the significant sexual dimorphism of cannabinoid actions, which will have to be taken into account in future animal and clinical studies.
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http://dx.doi.org/10.1111/adb.12940DOI Listing
May 2021

Ribosomal Protein S6 Hypofunction in Postmortem Human Brain Links mTORC1-Dependent Signaling and Schizophrenia.

Front Pharmacol 2020 24;11:344. Epub 2020 Mar 24.

Department of Pharmacology, University of the Basque Country UPV/EHU and Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Leioa, Spain.

The mechanistic target of rapamycin (also known as mammalian target of rapamycin) (mTOR)-dependent signaling pathway plays an important role in protein synthesis, cell growth, and proliferation, and has been linked to the development of the central nervous system. Recent studies suggest that mTOR signaling pathway dysfunction could be involved in the etiopathogenesis of schizophrenia. The main goal of this study was to evaluate the status of mTOR signaling pathway in postmortem prefrontal cortex (PFC) samples of subjects with schizophrenia. For this purpose, we quantified the protein expression and phosphorylation status of the mTOR downstream effector ribosomal protein S6 as well as other pathway interactors such as Akt and GSK3β. Furthermore, we quantified the status of these proteins in the brain cortex of rats chronically treated with the antipsychotics haloperidol, clozapine, or risperidone. We found a striking decrease in the expression of total S6 and in its active phosphorylated form phospho-S6 (Ser235/236) in the brain of subjects with schizophrenia compared to matched controls. The chronic treatment with the antipsychotics haloperidol and clozapine affected both the expression of GSK3β and the activation of Akt [phospho-Akt (Ser473)] in rat brain cortex, while no changes were observed in S6 and phospho-S6 (Ser235/236) protein expression with any antipsychotic treatment. These findings provide further evidence for the involvement of the mTOR-dependent signaling pathway in schizophrenia and suggest that a hypofunctional S6 may have a role in the etiopathogenesis of this disorder.
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http://dx.doi.org/10.3389/fphar.2020.00344DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105616PMC
March 2020

Bicyclic α-Iminophosphonates as High Affinity Imidazoline I Receptor Ligands for Alzheimer's Disease.

J Med Chem 2020 04 19;63(7):3610-3633. Epub 2020 Mar 19.

Laboratory of Medicinal Chemistry (Associated Unit to CSIC), Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institute of Biomedicine (IBUB), University of Barcelona, Av. Joan XXIII, 27-31, E-08028 Barcelona, Spain.

Imidazoline I receptors (I-IR), widely distributed in the CNS and altered in patients that suffer from neurodegenerative disorders, are orphans from a structural point of view, and new I-IR ligands are urgently required for improving their pharmacological characterization. We report the synthesis and three-dimensional quantitative structure-activity relationship (3D-QSAR) studies of a new family of bicyclic α-iminophosphonates endowed with relevant affinities for human brain I-IR. Acute treatment in mice with a selected compound significantly decreased Fas-associated protein with death domain (FADD) in the hippocampus, a key signaling mediator of neuroprotective actions. Additionally, studies in the familial Alzheimer's disease 5xFAD murine model revealed beneficial effects in behavior and cognition. These results are supported by changes in molecular pathways related to cognitive decline and Alzheimer's disease. Therefore, bicyclic α-iminophosphonates are tools that may open new therapeutic avenues for I-IR, particularly for unmet neurodegenerative conditions.
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http://dx.doi.org/10.1021/acs.jmedchem.9b02080DOI Listing
April 2020

Long-term hippocampal interneuronopathy drives sex-dimorphic spatial memory impairment induced by prenatal THC exposure.

Neuropsychopharmacology 2020 04 26;45(5):877-886. Epub 2020 Jan 26.

Department of Biochemistry and Molecular Biology, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Instituto Universitario de Investigación Neuroquímica (IUIN), Complutense University, 28040, Madrid, Spain.

Prenatal exposure to Δ-tetrahydrocannabinol (THC), the most prominent active constituent of cannabis, alters neurodevelopmental plasticity with a long-term functional impact on adult offspring. Specifically, THC affects the development of pyramidal neurons and GABAergic interneurons via cannabinoid CB receptors (CBR). However, the particular contribution of these two neuronal lineages to the behavioral alterations and functional deficits induced by THC is still unclear. Here, by using conditional CBR knockout mice, we investigated the neurodevelopmental consequences of prenatal THC exposure in adulthood, as well as their potential sex differences. Adult mice that had been exposed to THC during embryonic development showed altered hippocampal oscillations, brain hyperexcitability, and spatial memory impairment. Remarkably, we found a clear sexual dimorphism in these effects, with males being selectively affected. At the neuronal level, we found a striking interneuronopathy of CCK-containing interneurons in the hippocampus, which was restricted to male progeny. This THC-induced CCK-interneuron reduction was not evident in mice lacking CBR selectively in GABAergic interneurons, thus pointing to a cell-autonomous THC action. In vivo electrophysiological recordings of hippocampal LFPs revealed alterations in hippocampal oscillations confined to the stratum pyramidale of CA1 in male offspring. In addition, sharp-wave ripples, a major high-frequency oscillation crucial for learning and memory consolidation, were also altered, pointing to aberrant circuitries caused by persistent reduction of CCK basket cells. Taken together, these findings provide a mechanistic explanation for the long-term interneuronopathy responsible for the sex-dimorphic cognitive impairment induced by prenatal THC.
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http://dx.doi.org/10.1038/s41386-020-0621-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7075920PMC
April 2020

Functional coupling of M muscarinic acetylcholine receptor to Gα in dorsolateral prefrontal cortex from patients with psychiatric disorders: a postmortem study.

Eur Arch Psychiatry Clin Neurosci 2020 Oct 5;270(7):869-880. Epub 2019 Dec 5.

Laboratory of Neuropharmacology, IUNICS/IdISPa, University of the Balearic Islands (UIB), Palma de Mallorca, Spain.

Accumulating studies have implicated intracellular signaling through muscarinic acetylcholine receptors (mAChRs) in psychiatric illness. In the present study, carbamylcholine chloride (carbachol)-induced Gα and Gα activation was identified in postmortem human prefrontal cortical membranes. The following two sample cohorts were used: subjects [1], consisting of 40 controls without neuropsychiatric disorders, and subjects [2], consisting of 20 with bipolar disorder (BP), 20 major depressive disorder (MDD), 20 schizophrenia, and 20 controls, strictly sex- and age-matched. Carbachol-stimulated [S]GTPγS binding to human brain membranes was assessed by the two methods, i.e., conventional method using filtration techniques (Gα activation coupled to M/M mAChRs) applied to subjects [1], and [S]GTPγS binding/immuno precipitation assay (Gα activation coupled to M mAChR) applied to subjects [1] and [2]. The concentration eliciting the half-maximal effect (EC), maximum percent increase (%E), and slope factor were obtained from concentration-response curve of carbachol-induced Gα and Gα activation. The pEC values of both carbachol-induced Gα and Gα activations in subjects [1] were significantly correlated, though its implications or underlying molecular processes are unclear. The results of M mAChR-mediated Gα activation in subjects [2] indicated no significant disorder-specific alterations. However, the distribution patterns of the pEC values showed unequal variances among the groups. There was a significant inverse correlation between the %E values and the pEC values in subjects with schizophrenia, but not in those with BP or MDD, or controls. These data support the notion that schizophrenia patients consist of biologically heterogeneous subgroups with respect to M mAChR-mediated signaling pathways.
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http://dx.doi.org/10.1007/s00406-019-01088-9DOI Listing
October 2020

Serotonin 5-HT receptor expression and functionality in postmortem frontal cortex of subjects with schizophrenia: Selective biased agonism via G-proteins.

Eur Neuropsychopharmacol 2019 12 14;29(12):1453-1463. Epub 2019 Nov 14.

Department of Pharmacology, University of the Basque Country UPV/EHU, 48940 Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM, Spain; Biocruces Bizkaia Health Research Institute, Spain. Electronic address:

Serotonin 5-HT receptors (5-HTRs) have been implicated in schizophrenia. However, postmortem studies on 5-HTRs expression and functionality in schizophrenia are scarce. The 5-HTR mRNA and immunoreactive protein expression were evaluated in postmortem tissue from dorsolateral prefrontal cortex (DLPFC) of antipsychotic-free (n = 18) and antipsychotic-treated (n = 9) subjects with schizophrenia, and matched controls (n = 27). Functional coupling of 5-HTR to G-proteins was tested by measuring the activation induced by the agonist (±)-2,5-dimethoxy-4-iodoamphetamine hydrochloride ((±)DOI) in antibody-capture [S]GTPγS scintillation proximity assays (SPA). In antipsychotic-free schizophrenia subjects, 5-HTR mRNA expression and protein immunoreactivity in total homogenates was similar to controls. In contrast, in antipsychotic-treated schizophrenia subjects, lower mRNA expression (60±9% vs controls) and a trend to reduced protein immunoreactivity (86±5% vs antipsychotic-free subjects) just in membrane-enriched fractions was observed. [S]GTPγS SPA revealed a significant ~6% higher stimulation of G-protein by (±)DOI in schizophrenia, whereas activation of the canonical G-protein pathway by (±)DOI remained unchanged. Expression of G- and G-proteins did not differ between groups. Accordingly, in rats chronically treated with clozapine, but not with haloperidol, a 30-40% reduction was observed in 5-HTR mRNA expression, 5-HTR protein immunoreactivity and [H]ketanserin binding in brain cortical membranes. Overall, the data suggest a supersensitive 5-HTR signaling through inhibitory G-proteins in schizophrenia. Together with previous results, a dysfunctional pro-hallucinogenic agonist-sensitive 5-HTR conformation in postmortem DLPFC of subjects with schizophrenia is proposed. Atypical antipsychotic treatment would contribute to counterbalance this 5-HTR supersensitivity by reducing receptor expression.
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http://dx.doi.org/10.1016/j.euroneuro.2019.10.013DOI Listing
December 2019

Endocannabinoid system imbalance in the postmortem prefrontal cortex of subjects with schizophrenia.

J Psychopharmacol 2019 09 25;33(9):1132-1140. Epub 2019 Jun 25.

Department of Pharmacology, University of the Basque Country UPV/EHU, Leioa, Spain.

Background: The endocannabinoid system - comprising cannabinoid receptors, endocannabinoid ligands and their synthesis and inactivation enzymes - has been widely implicated in the pathophysiology of schizophrenia. However, little is known regarding the status of the different elements of the endocannabinoid system in the brain of schizophrenic patients. We have previously reported altered endocannabinoid levels in the postmortem brain of subjects with schizophrenia compared with matched controls.

Aims: Our aim was to further examine the status of the main elements of the endocannabinoid system in the postmortem prefrontal cortex of the same cohort of subjects.

Methods: Gene expression and function of the cannabinoid receptor type-1 (CB1) and the endocannabinoid degrading enzymes fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL) have been assessed.

Results: A significant decrease in mRNA levels in schizophrenia was found, without alteration of or mRNA expression. Moreover, positive correlations among mRNA expressions of the three genes studied were found in the prefrontal cortex of controls but not in schizophrenic subjects. No alteration was found in CB1 receptor mediated functional coupling to G-proteins, but a significant increase of FAAH activity was found in schizophrenic subjects compared with controls. 2-arachidonoylglycerol levels and MAGL activity were found to positively correlate in controls but not in schizophrenic subjects.

Conclusions: The present findings reveal an imbalance in the expression and function of different elements of the endocannabinoid system in schizophrenia. This outcome highlights the relevance of the endocannabinoid system in the pathophysiology of schizophrenia and emphasises its elements as potential targets in the search for new therapeutic strategies.
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http://dx.doi.org/10.1177/0269881119857205DOI Listing
September 2019

Sudden cardiac death associated to substances of abuse and psychotropic drugs consumed by young people: A population study based on forensic autopsies.

Drug Alcohol Depend 2019 08 29;201:23-28. Epub 2019 May 29.

Department of Pharmacology, University of the Basque Country, UPV/EHU, Leioa, Bizkaia, Spain; Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Spain; Biocruces Health Research Institute, Barakaldo, Bizkaia, Spain.

Background: Toxic substances are one of the main risk factors for sudden cardiac death (SCD) in young people. However, there is limited information about this matter based on clinical research. The aim of this study was to analyze the use of substances of abuse (legal and illicit) and prescribed psychotropic drugs in young people who died by SCD.

Methods: A population-based study performed in 15-35-year-olds who died by SCD in Biscay (Basque-Country) between 1991 and 2016. Cases were analyzed prospectively by a complete autopsy, toxicological and histopathological studies. A case was considered positive for exposure to cardiotoxic substances if smoking status was diagnosed or if toxicological analysis detected any drug associated with increased risk of SCD.

Results: There were 204 SCD; 98 (48%) were exposed to a cardiotoxic substance, including smoking status (n = 72) and/or positive toxicology (n = 58). Illicit drugs (n = 29, mainly cannabis and cocaine), ethanol (n = 25), and prescribed psychotropic drugs (n = 11) were detected. Positive cases were more frequent in males than in females (54% vs. 19%). They were also more common in subjects who died by acute (86%) and chronic (71%) ischemic heart disease than in myocardial diseases (33%) and sudden arrhythmic death syndrome (36%). All positive cases of illicit drugs were males. Smoking status was very high in deaths due to acute ischemic heart disease.

Conclusions: The proportion of users of substances of abuse was unexpectedly high, even more prevalent than other cardiovascular risk factors. Toxic substances could play an important role as triggers of SCD in young people.
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http://dx.doi.org/10.1016/j.drugalcdep.2019.03.021DOI Listing
August 2019

Cartography of hevin-expressing cells in the adult brain reveals prominent expression in astrocytes and parvalbumin neurons.

Brain Struct Funct 2019 Apr 17;224(3):1219-1244. Epub 2019 Jan 17.

Sorbonne Université, INSERM, CNRS, Neuroscience Paris Seine, Institut de Biologie Paris Seine, Paris, France.

Hevin, also known as SPARC-like 1, is a member of the secreted protein acidic and rich in cysteine family of matricellular proteins, which has been implicated in neuronal migration and synaptogenesis during development. Unlike previously characterized matricellular proteins, hevin remains strongly expressed in the adult brain in both astrocytes and neurons, but its precise pattern of expression is unknown. The present study provides the first systematic description of hevin mRNA distribution in the adult mouse brain. Using isotopic in situ hybridization, we showed that hevin is strongly expressed in the cortex, hippocampus, basal ganglia complex, diverse thalamic nuclei and brainstem motor nuclei. To identify the cellular phenotype of hevin-expressing cells, we used double fluorescent in situ hybridization in mouse and human adult brains. In the mouse, hevin mRNA was found in the majority of astrocytes but also in specific neuronal populations. Hevin was expressed in almost all parvalbumin-positive projection neurons and local interneurons. In addition, hevin mRNA was found in: (1) subsets of other inhibitory GABAergic neuronal subtypes, including calbindin, cholecystokinin, neuropeptide Y, and somatostatin-positive neurons; (2) subsets of glutamatergic neurons, identified by the expression of the vesicular glutamate transporters VGLUT1 and VGLUT2; and (3) the majority of cholinergic neurons from motor nuclei. Hevin mRNA was absent from all monoaminergic neurons and cholinergic neurons of the ascending pathway. A similar cellular profile of expression was observed in human, with expression of hevin in parvalbumin interneurons and astrocytes in the cortex and caudate nucleus as well as in cortical glutamatergic neurons. Furthermore, hevin transcript was enriched in ribosomes of astrocytes and parvalbumin neurons providing a direct evidence of hevin mRNAs translation in these cell types. This study reveals the unique and complex expression profile of the matricellular protein hevin in the adult brain. This distribution is compatible with a role of hevin in astrocytic-mediated adult synaptic plasticity and in the regulation of network activity mediated by parvalbumin-expressing neurons.
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http://dx.doi.org/10.1007/s00429-019-01831-xDOI Listing
April 2019

Optimization and pharmacological characterization of receptor-mediated G activation in postmortem human prefrontal cortex.

Basic Clin Pharmacol Toxicol 2019 Jun 4;124(6):649-659. Epub 2019 Jan 4.

Laboratory of Neuropharmacology, Institut Universitari d'Investigació en Ciències de la Salut (IUNICS), University of the Balearic Islands (UIB), Balearic Islands Health Research Institute (IdISBa), Palma de Mallorca, Spain.

The biochemical abnormalities in transmembrane signal transduction mediated through G protein-coupled receptors (GPCRs) have been postulated as underlying pathophysiology of psychiatric diseases such as schizophrenia and mood disorders. In the present study, the experimental conditions of agonist-induced [ S]GTPγS binding in postmortem human brain membranes were optimized, and the responses induced by a series of agonists were pharmacologically characterized. The [ S]GTPγS binding assay was performed in postmortem human prefrontal cortical membranes by means of filtration techniques, and standardized as to GDP concentration, membrane protein content, MgCl and NaCl concentrations in assay buffer, incubation period and effect of white matter contamination. Under the standard assay conditions, the specific [ S]GTPγS binding was stimulated by the addition of 15 compounds in a concentration-dependent manner. Of these agonists, R(+)-8-OH-DPAT, UK-14,304, DAMGO and DPDPE showed apparently biphasic concentration-response curves. As for these four responses, only higher-potency site was pharmacologically characterized. The receptors involved in the responses investigated were 5-HT receptor (probed with R(+)-8-OH-DPAT or 5-HT), α -adrenoceptor (UK-14,304 or (-)-epinephrine), M /M mAChRs (carbachol), adenosine A receptor (adenosine), histamine H receptor (histamine), group II mGlu (l-glutamate), GABA receptor (baclofen), μ-opioid receptor (DAMGO or endomophin-1), δ-opioid receptor (DPDPE or SNC-80) and NOP (nociceptin). Although dopamine also activated specific [ S]GTPγS binding, this response was likely mediated via α -adrenoceptor, but not dopamine receptor subtypes. The present study provides us with fundamental aspects of the strategy for elucidation of probable abnormalities of neural signalling mediated by G proteins activated through multiple GPCRs in the brain of psychiatric patients.
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http://dx.doi.org/10.1111/bcpt.13183DOI Listing
June 2019

Behavioral and Cognitive Improvement Induced by Novel Imidazoline I Receptor Ligands in Female SAMP8 Mice.

Neurotherapeutics 2019 04;16(2):416-431

Pharmacology Section, Department of Pharmacology, Toxicology and Medicinal Chemistry, Faculty of Pharmacy and Food Sciences, and Institut de Neurociències, University of Barcelona, Av. Joan XXIII, 27-31, 08028, Barcelona, Spain.

As populations increase their life expectancy, age-related neurodegenerative disorders such as Alzheimer's disease have become more common. I-Imidazoline receptors (I-IR) are widely distributed in the central nervous system, and dysregulation of I-IR in patients with neurodegenerative diseases has been reported, suggesting their implication in cognitive impairment. This evidence indicates that high-affinity selective I-IR ligands potentially contribute to the delay of neurodegeneration. In vivo studies in the female senescence accelerated mouse-prone 8 mice have shown that treatment with I-IR ligands, MCR5 and MCR9, produce beneficial effects in behavior and cognition. Changes in molecular pathways implicated in oxidative stress, inflammation, synaptic plasticity, and apoptotic cell death were also studied. Furthermore, treatments with these I-IR ligands diminished the amyloid precursor protein processing pathway and increased Aβ degrading enzymes in the hippocampus of SAMP8 mice. These results collectively demonstrate the neuroprotective role of these new I-IR ligands in a mouse model of brain aging through specific pathways and suggest their potential as therapeutic agents in brain disorders and age-related neurodegenerative diseases.
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http://dx.doi.org/10.1007/s13311-018-00681-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6554384PMC
April 2019

Differential α- and α-adrenoceptor protein expression in presynaptic and postsynaptic density fractions of postmortem human prefrontal cortex.

J Psychopharmacol 2019 02 26;33(2):244-249. Epub 2018 Sep 26.

1 Department of Pharmacology, University of the Basque Country, UPV/EHU, Leioa, Spain.

Background: Three different α-adrenoceptor (α-AR) subtypes have been described. The α-AR and α-AR subtypes are highly expressed in the human prefrontal cortex, where they modulate neurotransmission. However, due to the lack of subtype-selective ligands, the physiological relevance of both subtypes has not been fully resolved.

Aims: In this context, the aim of the present study was to characterize the protein expression of both α-AR subtypes, in different synaptic fractions of postmortem human prefrontal cortex.

Methods: A subcellular fractionation of the samples was performed and the protein expression of α- and α-ARs was measured in presynaptic membranes and postsynaptic density fractions by Western blot.

Results: The results revealed that the α-AR subtype is mainly located postsynaptically (95±3%) whereas the remaining 5±3% is in the presynapse. Conversely, the α-AR subtype showed a similar distribution between pre- and postsynaptic membranes, with a slightly higher percentage present in the presynapse (60±2% vs. 40±2%).

Conclusions: These findings could explain some contradictory effects reported for α-AR agonists and antagonists in the human prefrontal cortex. Furthermore, the present data could contribute to elucidating the therapeutic potential of selectively targeting α- or α-AR subtypes.
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http://dx.doi.org/10.1177/0269881118798612DOI Listing
February 2019

Differential α- and α-adrenoceptor protein expression in presynaptic and postsynaptic density fractions of postmortem human prefrontal cortex.

J Psychopharmacol 2019 02 26;33(2):244-249. Epub 2018 Sep 26.

1 Department of Pharmacology, University of the Basque Country, UPV/EHU, Leioa, Spain.

Background: Three different α-adrenoceptor (α-AR) subtypes have been described. The α-AR and α-AR subtypes are highly expressed in the human prefrontal cortex, where they modulate neurotransmission. However, due to the lack of subtype-selective ligands, the physiological relevance of both subtypes has not been fully resolved.

Aims: In this context, the aim of the present study was to characterize the protein expression of both α-AR subtypes, in different synaptic fractions of postmortem human prefrontal cortex.

Methods: A subcellular fractionation of the samples was performed and the protein expression of α- and α-ARs was measured in presynaptic membranes and postsynaptic density fractions by Western blot.

Results: The results revealed that the α-AR subtype is mainly located postsynaptically (95±3%) whereas the remaining 5±3% is in the presynapse. Conversely, the α-AR subtype showed a similar distribution between pre- and postsynaptic membranes, with a slightly higher percentage present in the presynapse (60±2% vs. 40±2%).

Conclusions: These findings could explain some contradictory effects reported for α-AR agonists and antagonists in the human prefrontal cortex. Furthermore, the present data could contribute to elucidating the therapeutic potential of selectively targeting α- or α-AR subtypes.
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http://dx.doi.org/10.1177/0269881118798612DOI Listing
February 2019

Intracellular inflammatory and antioxidant pathways in postmortem frontal cortex of subjects with major depression: effect of antidepressants.

J Neuroinflammation 2018 Sep 4;15(1):251. Epub 2018 Sep 4.

Centro de Investigación Biomédica en Red de Salud Mental (CIBERSAM), Instituto de Salud Carlos III (ISCIII), C/ Monforte de Lemos 3-5, 28029, Madrid, Spain.

Background: Studies show that Toll-like receptors (TLRs), members of the innate immune system, might participate in the pathogenesis of the major depressive disorder (MDD). However, evidence of this participation in the brain of patients with MDD has been elusive.

Methods: This work explores whether the protein expression by immunodetection assays (Western blot) of elements of TLR-4 pathways controlling inflammation and the oxidative/nitrosative stress are altered in postmortem dorsolateral prefrontal cortex of subjects with MDD. The potential modulation induced by the antidepressant treatment on these parameters was also assessed. Thirty MDD subjects (15 antidepressant-free and 15 under antidepressant treatment) were matched for gender and age to 30 controls in a paired design.

Results: No significant changes in TLR-4 expression were detected. An increased expression of the TLR-4 endogenous ligand Hsp70 (+ 33%), but not of Hsp60, and the activated forms of mitogen-activated protein kinases (MAPKs) p38 (+ 47%) and JNK (+ 56%) was observed in MDD. Concomitantly, MDD subjects present a 45% decreased expression of DUSP2 (a regulator of MAPKs) and reduced (- 21%) expression of the antioxidant nuclear factor Nrf2. Antidepressant treatment did not modify the changes detected in the group with MDD and actually increased (+ 25%) the expression of p11, a protein linked with the transport of neurotransmitters and depression.

Conclusion: Data indicate an altered TLR-4 immune response in the brain of subjects with MDD. Additional research focused on the mechanisms contributing to the antidepressant-induced TLR-4 pathway modulation is warranted and could help to develop new treatment strategies for MDD.
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http://dx.doi.org/10.1186/s12974-018-1294-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6122627PMC
September 2018

The endocannabinoid system in mental disorders: Evidence from human brain studies.

Biochem Pharmacol 2018 11 17;157:97-107. Epub 2018 Jul 17.

Department of Pharmacology, University of the Basque Country UPV/EHU, Leioa, Spain; Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Spain; Biocruces Health Research Institute, Bizkaia, Spain. Electronic address:

Mental disorders have a high prevalence compared with many other health conditions and are the leading cause of disability worldwide. Several studies performed in the last years support the involvement of the endocannabinoid system in the etiopathogenesis of different mental disorders. The present review will summarize the latest information on the role of the endocannabinoid system in psychiatric disorders, specifically depression, anxiety, and schizophrenia. We will focus on the findings from human brain studies regarding alterations in endocannabinoid levels, cannabinoid receptors and endocannabinoid metabolizing enzymes in patients suffering mental disorders. Studies carried out in humans have consistently demonstrated that the endocannabinoid system is fundamental for emotional homeostasis and cognitive function. Thus, deregulation of the different elements that are part of the endocannabinoid system may contribute to the pathophysiology of several mental disorders. However, the results reported are controversial. In this sense, different alterations in gene and/or protein expression of CB1 receptors have been shown depending on the technical approach used or the brain region studied. Despite the current discrepancies regarding cannabinoid receptors changes in depression and schizophrenia, present findings point to the endocannabinoid system as a pivotal neuromodulatory pathway relevant in the pathophysiology of mental disorders.
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http://dx.doi.org/10.1016/j.bcp.2018.07.009DOI Listing
November 2018

Chronic cannabis promotes pro-hallucinogenic signaling of 5-HT2A receptors through Akt/mTOR pathway.

Neuropsychopharmacology 2018 09 27;43(10):2028-2035. Epub 2018 Apr 27.

Department of Pharmacology, University of the Basque Country UPV/EHU and Centro de Investigación Biomédica en Red de Salud Mental CIBERSAM, Leioa, Spain.

Long-term use of potent cannabis during adolescence increases the risk of developing schizophrenia later in life, but to date, the mechanisms involved remain unknown. Several findings suggest that the functional selectivity of serotonin 2A receptor (5-HT2AR) through inhibitory G-proteins is involved in the molecular mechanisms responsible for psychotic symptoms. Moreover, this receptor is dysregulated in the frontal cortex of schizophrenia patients. In this context, studies involving cannabis exposure and 5-HT2AR are scarce. Here, we tested in mice the effect of an early chronic Δ-tetrahydrocannabinol (THC) exposure on cortical 5-HT2AR expression, as well as on its in vivo and in vitro functionality. Long-term exposure to THC induced a pro-hallucinogenic molecular conformation of the 5-HT2AR and exacerbated schizophrenia-like responses, such as prepulse inhibition disruption. Supersensitive coupling of 5-HT2AR toward inhibitory Gαi1-, Gαi3-, Gαo-, and Gαz-proteins after chronic THC exposure was observed, without changes in the canonical Gαq/11-protein pathway. In addition, we found that inhibition of Akt/mTOR pathway by rapamycin blocks the changes in 5-HT2AR signaling pattern and the supersensitivity to schizophrenia-like effects induced by chronic THC. The present study provides the first evidence of a mechanistic explanation for the relationship between chronic cannabis exposure in early life and increased risk of developing psychosis-like behaviors in adulthood.
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http://dx.doi.org/10.1038/s41386-018-0076-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6098160PMC
September 2018