Effect of chronic stress on cardiovascular function in normotensive and hypertensive female rats

• Grant number: 13/20228-6
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): January 01, 2014
• Effective date (End): July 31, 2017
• Field of knowledge: Biological Sciences - Pharmacology - Neuropsychopharmacology
• Principal researcher: Carlos Cesar Crestani
• Grantee: Jonas de Oliveira Vieira
• Home Institution: Faculdade de Ciências Farmacêuticas (FCFAR). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Studies have demonstrated a direct relationship between stress and cardiovascular diseases. Although the importance of this issue, the mechanisms and factors involved in association between stress and cardiovascular complications is poorly investigated. Clinical and preclinical studies have pointed that female individuals are more vulnerable to behavioral and neuroendocrine consequences of the stress. However, the effect of chronic stress on cardiovascular function of females is poorly investigated. Therefore, the general aim of the present propose is to investigate the consequences of chronic stress protocols on cardiovascular function in female rats. In addition to sexual dimorphism, it has been proposed that behavioral and physiological changes evoked by stress are related to characteristics of the aversive stimuli. However, there is not evidence in the literature about the influence of the type of stress in cardiovascular changes evoked by repeated exposure to stressful events. In this way, a second aim of the present study is to compare the consequences of two protocols of chronic stress (variable chronic stress and repeated restraint stress) on cardiovascular function. Finally, studies in humans and animals have reported that the sympathetic activation and cardiovascular changes observed during an acute session of stress are exacerbated in hypertensive, when compared with normotensive. However, evidence of the consequences of long-term exposure to aversive stimuli on cardiovascular function in hypertensive is limited. Moreover, previous preclinical studies were conducted in male animals, and there is no evidence in hypertensive females. Thus, the aims in the present study are: 1) to investigate the vulnerability of normotensive female rats, when compared to normotensive male rats, in the consequences of the chronic variable stress and the repeated exposure to restraint stress on cardiovascular function; and 2) to investigate the vulnerability of hypertensive female rats, when compared with normotensive female rats, in the consequences of the chronic variable stress and the repeated exposure to restraint stress on cardiovascular function. For evaluation of cardiovascular function, we will investigate the effect of the chronic stress protocols on basal parameters of arterial pressure and heart rate, baroreflex activity, vascular reactivity to vasoactive agents and the cardiac autonomic balance. (AU)