Publications by authors named "Léa J Becker"

6 Publications

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Enhanced analgesic cholinergic tone in the spinal cord in a mouse model of neuropathic pain.

Neurobiol Dis 2021 Apr 18;155:105363. Epub 2021 Apr 18.

Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, 67000 Strasbourg, France; University of Strasbourg Institute for Advanced Study (USIAS), 67000 Strasbourg, France. Electronic address:

Endogenous acetylcholine (ACh) is an important modulator of nociceptive sensory processing in the spinal cord. An increased level of spinal ACh induces analgesia both in humans and rodents while interfering with cholinergic signaling is allodynic, demonstrating that a basal tone of spinal ACh modulates nociceptive responses in naïve animals. The plasticity undergone by this cholinergic system in chronic pain situation is unknown, and the mere presence of this tone in neuropathic animals is controversial. We have addressed these issues in mice through behavioral experiments, histology, electrophysiology and molecular biology, in the cuff model of peripheral neuropathy. Our behavior experiments demonstrate the persistence, and even increased impact of the analgesic cholinergic tone acting through nicotinic receptors in cuff animals. The neuropathy does not affect the number or membrane properties of dorsal horn cholinergic neurons, nor specifically the frequency of their synaptic inputs. The alterations thus appear to be in the neurons receiving the cholinergic signaling, which is confirmed by the fact that subthreshold doses of acetylcholinesterase (AChE) inhibitors in sham animals become anti-allodynic in cuff mice and by the altered expression of the β2 nicotinic receptor subunit. Our results demonstrate that endogenous cholinergic signaling can be manipulated to relieve mechanical allodynia in animal models of peripheral neuropathy. Until now, AChE inhibitors have mainly been used in the clinics in situations of acute pain (parturition, post-operative). The fact that lower doses (thus with fewer side effects) could be efficient in chronic pain conditions opens new avenues for the treatment of neuropathic pain. SIGNIFICANCE STATEMENT: Chronic pain continues to be the most common cause of disability that impairs the quality of life, accruing enormous and escalating socio-economic costs. A better understanding of the plasticity of spinal neuronal networks, crucially involved in nociceptive processing, could help designing new therapeutic avenues. We here demonstrate that chronic pain modifies the spinal nociceptive network in such a way that it becomes more sensitive to cholinergic modulations. The spinal cholinergic system is responsible for an analgesic tone that can be exacerbated by acetylcholinesterase inhibitors, a property used in the clinic to relief acute pain (child birth, post-op). Our results suggest that lower doses of acetylcholinesterases, with even fewer side effects, could be efficient to relieve chronic pain.
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http://dx.doi.org/10.1016/j.nbd.2021.105363DOI Listing
April 2021

Action of mefloquine/amitriptyline THN101 combination on neuropathic mechanical hypersensitivity in mice.

Pain 2021 Mar 24. Epub 2021 Mar 24.

Centre National de la Recherche Scientifique, Université de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France Theranexus, Lyon, France.

Abstract: Tricyclic antidepressants that inhibit serotonin and noradrenaline reuptake, such as amitriptyline, are among the first-line treatments for neuropathic pain, which is caused by a lesion or disease affecting the somatosensory nervous system. These treatments are, however, partially efficient to alleviate neuropathic pain symptoms, and better treatments are still highly required. Interactions between neurons and glial cells participate in neuropathic pain processes, and importantly, connexins-transmembrane proteins involved in cell-cell communication-contribute to these interactions. In a neuropathic pain model in rats, mefloquine, a connexin inhibitor, has been shown to potentiate the antihyperalgesic effect of amitriptyline, a widely used antidepressant. In this study, we further investigated this improvement of amitriptyline action by mefloquine, using the cuff model of neuropathic pain in mice. We first observed that oral mefloquine co-treatment prolonged the effect of amitriptyline on mechanical hypersensitivity by 12 hours after administration. In addition, we showed that this potentiation was not due to pharmacokinetic interactions between the 2 drugs. Besides, lesional and pharmacological approaches showed that the prolonged effect was induced through noradrenergic descending pathways and the recruitment of α2 adrenoceptors. Another connexin blocker, carbenoxolone, also improved amitriptyline action. Additional in vitro studies suggested that mefloquine may also directly act on serotonin transporters and on adenosine A1 and A2A receptors, but drugs acting on these other targets failed to amplify amitriptyline action. Together, our data indicate that pharmacological blockade of connexins potentiates the therapeutic effect of amitriptyline in neuropathic pain.
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http://dx.doi.org/10.1097/j.pain.0000000000002276DOI Listing
March 2021

Comorbidity of chronic pain and anxiodepressive disorders: Deciphering underlying brain circuits.

Neurosci Biobehav Rev 2020 08 30;115:131-133. Epub 2020 May 30.

Centre National de la Recherche Scientifique, Université de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, Institut des Neurosciences Cellulaires et Intégratives UPR3212, 67000 Strasbourg, France; Department of Psychiatry and Neuroscience, Université Laval, Québec, Canada. Electronic address:

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http://dx.doi.org/10.1016/j.neubiorev.2020.05.013DOI Listing
August 2020

Ketamine induces rapid and sustained antidepressant-like effects in chronic pain induced depression: Role of MAPK signaling pathway.

Prog Neuropsychopharmacol Biol Psychiatry 2020 06 25;100:109898. Epub 2020 Feb 25.

Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique et Université de Strasbourg, 67000 Strasbourg, France. Electronic address:

Chronic pain produces psychologic distress, which often leads to mood disorders such as depression. Co-existing chronic pain and depression pose a serious socio-economic burden and result in disability affecting millions of individuals, which urges the development of treatment strategies targeting this comorbidity. Ketamine, a noncompetitive antagonist of the N-methyl-d-aspartate (NMDA) receptor, is shown to be efficient in treating both pain and depression-related symptoms. However, the molecular characteristics of its role in chronic pain-induced depression remain largely unexplored. Hence, we studied the behavioral and molecular effects of a single systemic administration of ketamine (15 mg/kg, i.p.) on mechanical hypersensitivity and depressive-like consequences of chronic neuropathic pain. We showed that ketamine transiently alleviated mechanical hypersensitivity (lasting <24 h), while its antidepressant effect was observed even 72 h after administration. In addition, ketamine normalized the upregulated expression of the mitogen activated protein kinase (MAPK) phosphatase 1 (MKP-1) and the downregulated phosphorylation of extracellular signal-regulated kinase (pERK) in the anterior cingulate cortex (ACC) of mice displaying neuropathic pain-induced depressive-like behaviors. This effect of ketamine on the MKP-1 was first detected 30 min after the ketamine administration and persisted until up to 72 h. Altogether, these findings provide insight into the behavioral and molecular changes associated with single ketamine administration in the comorbidity of chronic pain and depression.
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http://dx.doi.org/10.1016/j.pnpbp.2020.109898DOI Listing
June 2020

How to study anxiety and depression in rodent models of chronic pain?

Eur J Neurosci 2021 Jan 11;53(1):236-270. Epub 2020 Feb 11.

Centre National de la Recherche Scientifique, Institut des Neurosciences Cellulaires et Intégratives, Université de Strasbourg, Strasbourg, France.

Mood disorders such as depression and anxiety are frequently observed in patients suffering from chronic pain. Over time, different tests and models have been developed in rodents to study the anxiodepressive-like consequences of chronic pain. This review describes these preclinical tools (models and tests) used for studying behavioural aspects of the comorbid relationship between chronic pain and anxiety and/or major depressive disorder. Three major types of chronic pain strongly associated with anxiodepressive-like comorbidity as well as their animal models are presented: neuropathic pain, inflammatory pain and fibromyalgia. After a description of chronic pain animal models and of the tests that allow determining nociceptive responses, this review presents and discusses the various behavioural tests that have been used to assess anxiety and depressive-like behaviours in these models of chronic pain. Finally, this review highlights the progress that remains to be made to homogenize the results in the field of pain-induced mood disorders and summarizes the recent advances achieved through these tests and models.
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http://dx.doi.org/10.1111/ejn.14686DOI Listing
January 2021

Phenylpyridine-2-ylguanidines and rigid mimetics as novel inhibitors of TNFα overproduction: Beneficial action in models of neuropathic pain and of acute lung inflammation.

Eur J Med Chem 2018 Mar 31;147:163-182. Epub 2018 Jan 31.

CNRS, Université de Strasbourg, UMR7200 Laboratoire d' Innovation Thérapeutique, 67401 Illkirch, France; Labex MEDALIS, 67000 Strasbourg, France. Electronic address:

4-phenylpyridin-2-yl-guanidine (5b): a new inhibitor of the overproduction of pro-inflammatory cytokines (TNFα and Il1β) was identified from a high-throughput screening of a chemical library on human peripheral blood mononuclear cells (PBMCs) after LPS stimulation. Derivatives, homologues and rigid mimetics of 5b were designed and synthesized, and their cytotoxicity and ability to inhibit TNFα overproduction were evaluated. Among them, compound 5b and its mimetic 12 (2-aminodihydroquinazoline) showed similar inhibitory activities, and were evaluated in vivo in models of lung inflammation and neuropathic pain in mice. In particular, compound 12 proved to be active (5 mg/kg, ip) in both models.
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http://dx.doi.org/10.1016/j.ejmech.2018.01.049DOI Listing
March 2018