The paraventricular nucleus of the hypothalamus (PVN) has been implicated in several aspects of central cardiovascular control. The PVN has neural connections with several limbic structures involved with both autonomic and behavioral control during defensive situations. It has been reported that the PVN has a dissociated role on cardiovascular responses observed during acute restraint stress (AR). The PVN neurotransmission inhibition is characterized by reduction of the blood pressure increases without effect on tachycardiac response. The AR is an unavoidable stressor that causes mean arterial pressure increase and an intense tachycardiac response, with concomitant increase in the plasma concentrations of corticosterone and adrenocorticotrophin. Moreover, the stressful situations cause a reduction in temperature of the tail skin in rats. This decrease in temperature is due to skin vasoconstriction, and it is, together with cardiovascular alteration, an indicative of autonomic activity. Among the several neurotransmitters present in the PVN which have been reported to participate in cardiovascular modulation, attention has been called upon the glutamatergic and nitrergic systems. Therefore, the hypothesis of the present project is that an interaction between glutamatergic and nitrergic systems present in the PVN are involved with mediation of autonomic and hormonal changes caused by the exposure of rats to AR. To achieve this purpose we will study these neurotransmissions interaction on cardiovascular, temperature and hormonal effects induced by exposure to AR, by local PVN inhibition of both glutamatergic receptor and nitrergic system made before exposing animals to the stress.
News published in Agência FAPESP Newsletter about the scholarship: