Role of the autonomic nervous system and baroreflex in stress-evoked cardiovascular responses in rats

Author(s)

dos Reis, Daniel Gustavo ^[1] ; Trindade Fortaleza, Eduardo Albino ^[1] ; Tavares, Rodrigo Fiacadori ^[1] ; Aguiar Correa, Fernando Morgan ^[1]

Affiliation

^[1] Univ Sao Paulo, Dept Pharmacol, Sch Med Ribeirao Preto, BR-14049900 Sao Paulo - Brazil

• Document type: Journal article
• Source: STRESS-THE INTERNATIONAL JOURNAL ON THE BIOLOGY OF STRESS; v. 17, n. 4, p. 362-372, JUL 2014.
• Web of Science Citations: 19

Abstract

Restraint stress (RS) is an experimental model to study stress-related cardiovascular responses, characterized by sustained pressor and tachycardiac responses. We used pharmacologic and surgical procedures to investigate the role played by sympathetic nervous system (SNS) and parasympathetic nervous system (PSNS) in the mediation of stress-evoked cardiovascular responses. Ganglionic blockade with pentolinium significantly reduced RS-evoked pressor and tachycardiac responses. Intravenous treatment with homatropine methyl bromide did not affect the pressor response but increased tachycardia. Pretreatment with prazosin reduced the pressor and increased the tachycardiac response. Pretreatment with atenolol did not affect the pressor response but reduced tachycardia. The combined treatment with atenolol and prazosin reduced both pressor and tachycardiac responses. Adrenal demedullation reduced the pressor response without affecting tachycardia. Sinoaortic denervation increased pressor and tachycardiac responses. The results indicate that: (1) the RS-evoked cardiovascular response is mediated by the autonomic nervous system without an important involvement of humoral factors; (2) hypertension results primarily from sympathovascular and sympathoadrenal activation, without a significant involvement of the cardiac sympathetic component (CSNS); (3) the abrupt initial peak in the hypertensive response to restraint is sympathovascular-mediated, whereas the less intense but sustained hypertensive response observed throughout the remaining restraint session is mainly mediated by sympathoadrenal activation and epinephrine release; (4) tachycardia results from CSNS activation, and not from PSNS inhibition; (5) RS evokes simultaneous CSNS and PSNS activation, and heart rate changes are a vector of both influences; (6) the baroreflex is functional during restraint, and modulates both the vascular and cardiac responses to restraint. (AU)

• FAPESP's process: 11/21921-1 - The participation of the Medial prefrontal cortex in reconsolidation and extinction processes of the aversive conditioned memory: possible interaction between glutamate - nitric oxide pathway and the endocanabinoids
• Grantee: Daniel Gustavo dos Reis
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 12/18556-2 - Involvement of the glutamatergic system in the paraventricular and supra-optic nucleus on the modulation of the cardiovascular system and the vasopressin and oxytocin release, in rats submitted to osmotic stimuli.
• Grantee: Eduardo Albino Trindade Fortaleza
• Support Opportunities: Scholarships in Brazil - Post-Doctoral