Possible MECHANISMS INVOLVED IN PERIPHERAL CARDIOVASCULAR RESPONSES EVOKED BY THE ACTIVATION OF VENTRAL HIPPOCAMPUS NMDA RECEPTORS OF UNAESTHETIZED RATS

• Grant number: 11/13626-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2011
• End date: September 30, 2012
• Field of knowledge: Biological Sciences - Pharmacology - Autonomic Pharmacology
• Principal Investigator: Leonardo Resstel Barbosa Moraes
• Grantee: Cibele Santini de Oliveira
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

TThe hippocampus is a brain structure, which is part of the limbic system, involved in emotional processes, learning and memory. In rats, electrical stimulation of this area causes defensive reactions, also autonomic changes such as heart rate and blood pressure alterations, depending on the anesthetic used and the sub-region stimulated.In addition, the hippocampus is able to modulate cardiovascular and behavioral responses during aversive situations. Under stress there is an increased release of L-Glutamate (L-Glu) in the hippocampus, suggesting that this area has a glutamatergic system activated during defense reactions. It has been reported that activation of NMDA receptors by administration of L-Glu in regions of the central nervous system of rats causes increased blood pressure and heart rate through activation of the enzyme nitric oxide synthase (NOS). In the hippocampus, the activation of NMDA receptors is also involved in increased formation of NO.Previously, we administered different doses of L-Glu that caused dose-dependent cardiovascular responses. These responses were blocked by pretreatment with HV selective NMDA receptor antagonist AP-7, a selective inhibitor of nNOS-NÉ Argenine Propyl-L-(N-Propyl) and a kidnapper of NO, C-PTIO, showing the involvement of glutamatergic neurotransmission, Nitrergic in HV in the modulation of cardiovascular responses. However, the peripheral mechanisms responsible for increased blood pressure and heart rate triggered by microinjection of L-Glu in HV non-anesthetized rats have not been studied.The autonomic nervous system (ANS) has two divisions: sympathetic and a parasympathetic one. The central control of movement operates via parasympathetic neurons, which innervate the heart, and through three major classes of sympathetic efferents which innervate the heart, blood vessels, kidneys and adrenal medulla - barossensitivos, and termossensitivos glucosensitivos.Based on the knowledge of the mechanisms involved in autonomic cardiovascular control, this project's hypothesis that the pressor and tachycardia responses to microinjection of L-Glu in HV are mediated by sympathetic activation of SNA and / or inhibition of the parasympathetic SNA.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

SANTINI, CIBELE O.; FASSINI, ALINE; SCOPINHO, AMERICA A.; BUSNARDO, CRISTIANE; CORREA, FERNANDO M. A.; RESSTEL, LEONARDO B. M.. The ventral hippocampus NMDA receptor/nitric oxide/guanylate cyclase pathway modulates cardiovascular responses in rats. AUTONOMIC NEUROSCIENCE-BASIC & CLINICAL, v. 177, n. 2, p. 244-252, OCT 2013. (11/13626-0, 09/05308-8, 11/07332-3)