Publications by authors named "Marina de Toledo Durand"

4 Publications

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Cigarette smoke exposure causes systemic and autonomic cardiocirculatory changes in rats depending on the daily exposure dose.

Life Sci 2021 Jul 20;277:119498. Epub 2021 Apr 20.

Medical School, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil. Electronic address:

Aims: To evaluate the systemic changes and autonomic cardiocirculatory control of awaken rats chronically exposed to the cigarette smoke (CS) of 1 or 2 cigarettes/day.

Main Methods: Rats were exposed to clean air (control) or cigarette smoke of 1 (CS1) or 2 (CS2) cigarettes/animal/day for 30 days. Then, arterial pressure (AP) and heart rate (HR) were recorded in conscious rats to assess spontaneous baroreflex sensitivity and HR and AP variabilities. Evoked baroreflex and cardiac autonomic tone were evaluated by vasoactive drugs and autonomic blockers, respectively. In another group, ventilatory and cardiovascular parameters were recorded under hypoxia and hypercapnia stimulus. At the end of protocols, heart, lung, kidneys and liver were collected for histological analysis.

Key Findings: Rats exposed to CS showed morphological changes, being more evident in the CS2 group. Also, less weight gain and cardiac hypertrophy were prominent in CS2 rats. Basal AP and HR, spontaneous baroreflex sensitivity and cardiovascular variabilities were similar among groups. CS exposure progressively blunted the bradycardia response to phenylephrine (-2.2 ± 0.1 vs. -1.7 ± 0.2 vs. -1.5 ± 0.2) while the tachycardia response to sodium nitroprusside was slightly increased compared to control. Vagal tone was not affected by CS, but CS2 rats exhibited higher sympathetic tone (-25 ± 4 vs. -28 ± 4 vs. -56 ± 9) and lower intrinsic HR (411 ± 4 vs. 420 ± 8 vs. 390 ± 6). Exposure to CS of 2 cigarettes also exacerbated the reflex cardiovascular and ventilatory responses to hypoxia and hypercapnia.

Significance: CS exposure for 30 days promoted systemic changes and autonomic cardiocirculatory dysfunction in rats depending on the daily exposure dose.
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http://dx.doi.org/10.1016/j.lfs.2021.119498DOI Listing
July 2021

Activation of the Kinin B1 Receptor by Its Agonist Reduces Melanoma Metastasis by Playing a Dual Effect on Tumor Cells and Host Immune Response.

Front Pharmacol 2019 25;10:1106. Epub 2019 Sep 25.

Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil.

Metastatic melanoma is an aggressive type of skin cancer leading half of the patients to death within 8-10 months after diagnosis. Kinins are peptides that interact with B1 and B2 receptors playing diverse biological roles. We investigated whether treatment with B1 receptor agonist, des-Arg-bradykinin (DABK), has effects in lung metastasis establishment after melanoma induction in mice. We found a lower number of metastatic colonies in lungs of DABK-treated mice, reduced expression of vascular cell adhesion molecule 1 (VCAM-1), and increased CD8T-cell recruitment to the metastatic area compared to animals that did not receive treatment. To understand whether the effects of DABK observed were due to the activation of the B1 receptor in the tumor cells or in the host, we treated wild-type (WT) and kinin B1 receptor knockout (B1) mice with DABK. No significant differences in the number of melanoma colonies established in lungs were seen between WT and B1mice; however, B1mice presented higher VCAM-1 expression and lower CD8T-cell infiltration. In conclusion, we believe that activation of kinin B1 receptor by its agonist in the host stimulates the immune response more efficiently, promoting CD8T-cell recruitment to the metastatic lungs and interfering in VCAM-1 expression. Moreover, treatment with DABK reduced establishment of metastatic colonies by mainly acting on tumor cells; hence, this study brings insights to explore novel approaches to treat metastatic melanoma targeting the B1 receptor.
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http://dx.doi.org/10.3389/fphar.2019.01106DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6774293PMC
September 2019

Students' perception of animal or virtual laboratory in physiology practical classes in PBL medical hybrid curriculum.

Adv Physiol Educ 2019 Dec;43(4):451-457

University of Ribeirão Preto, Ribeirão Preto, Sao Paulo, Brazil.

Over the years, much criticism against animal use for physiology teaching has been made. Hence, replacement by suitable alternatives has increased in several pedagogical approaches. This study examined students' perceptions of animal versus virtual (video/computer) laboratory classes in physiological sciences associated with the effectiveness of the problem-based learning (PBL) hybrid curriculum. Three cohorts of medical students from the University of Ribeirão Preto, who participated in animal or virtual physiology classes or both, were asked to fill out a 5-point Likert questionnaire about knowledge acquisition/motivation, importance to PBL learning goals, skills acquired, need for animal use, academic formation, learning impairment, and alternative methods. We also assessed their grades in the final exam. A total of 350 students were included, in which 108 participated only in virtual classes, 120 only in practical animal laboratory classes, and 122 in both approaches. The majority agreed that the two methods improved their knowledge acquisition/motivation and helped to reinforce tutorial goals and to acquire skills. However, the cohort who experienced both approaches favored animal laboratory. Students believe animal use is needed and did not impair their learning. Conversely, their opinion about academic formation without animal laboratory classes was divided, as was whether this approach inspired them to seek alternative methods. Despite the different perceptions, there was no difference among the groups' final grades (7.3 ± 1 vs. 7.2 ± 1 vs. 7.2 ± 2 for virtual or practical animal laboratory classes or both, respectively). Therefore, virtual activities are not as effective as animal use in the opinions of the students, but they are successful strategies in physiology learning that can be used in practical classes in a hybrid PBL curriculum.
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http://dx.doi.org/10.1152/advan.00005.2019DOI Listing
December 2019

Hemodynamic responses to aortic depressor nerve stimulation in conscious L-NAME-induced hypertensive rats.

Am J Physiol Regul Integr Comp Physiol 2011 Feb 24;300(2):R418-27. Epub 2010 Nov 24.

Department of Physiology, School of Medicine of Ribeirão Preto, University of Sao Paulo, Sao Paulo, Brazil.

The present study investigated whether baroreflex control of autonomic function is impaired when there is a deficiency in NO production and the role of adrenergic and cholinergic mechanisms in mediating reflex responses. Electrical stimulation of the aortic depressor nerve in conscious normotensive and nitro-l-arginine methyl ester (L-NAME)-induced hypertensive rats was applied before and after administration of methylatropine, atenolol, and prazosin alone or in combination. The hypotensive response to progressive electrical stimulation (5 to 90 Hz) was greater in hypertensive (-27 ± 2 to -64 ± 3 mmHg) than in normotensive rats (-17 ± 1 to -46 ± 2 mmHg), whereas the bradycardic response was similar in both groups (-34 ± 5 to -92 ± 9 and -21 ± 2 to -79 ± 7 beats/min, respectively). Methylatropine and atenolol showed no effect in the hypotensive response in either group. Methylatropine blunted the bradycardic response in both groups, whereas atenolol attenuated only in hypertensive rats. Prazosin blunted the hypotensive response in both normotensive (43%) and hypertensive rats (53%) but did not affect the bradycardic response in either group. Prazosin plus angiotensin II, used to restore basal arterial pressure, provided hemodynamic responses similar to those of prazosin alone. The triple pharmacological blockade abolished the bradycardic response in both groups but displayed similar residual hypotensive response in hypertensive (-13 ± 2 to -27 ± 2 mmHg) and normotensive rats (-10 ± 1 to -25 ± 3 mmHg). In conclusion, electrical stimulation produced a well-preserved baroreflex-mediated decrease in arterial pressure and heart rate in conscious l-NAME-induced hypertensive rats. Moreover, withdrawal of the sympathetic drive played a role in the reflex bradycardia only in hypertensive rats. The residual fall in pressure after the triple pharmacological blockade suggests the involvement of a vasodilatory mechanism unrelated to NO or deactivation of α(1)-adrenergic receptor.
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http://dx.doi.org/10.1152/ajpregu.00463.2010DOI Listing
February 2011