Swimming exercise changes hemodynamic responses evoked by blockade of excitatory amino receptors in the rostral ventrolateral medulla in spontaneously hypertensive rats.

Exercise training reduces sympathetic activity in hypertensive humans and rats. We hypothesized that the swimming exercise would change the neurotransmission in the rostral ventrolateral medulla (RVLM), a key region involved in sympathetic outflow, and hemodynamic control in spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats. Bilateral injections of kynurenic acid (KYN) were carried out in the RVLM in sedentary- (S-) or exercised- (E-) SHR and WKY rats submitted to swimming for 6 weeks.

Characterization of the sleep-wake cycle of the Neotropical rodent Proechimys guyannensis.

Objectives: To better understand the sleep-wake cycle characteristics in the female Neotropical rodent Proechimys guyannensis related to comparative neurobiology.

Methods: Surface neocortical and hippocampal electrodes were chronically implanted in the brains of female Wistar and Proechimys animals. In addition, electrodes for the study of muscle activity were implanted into the neck muscle of both species.

Exercise changes regional vascular control by commissural NTS in spontaneously hypertensive rats.

Inhibition of the commissural nucleus of the solitary tract (commNTS) induces a fall in sympathetic nerve activity and blood pressure in spontaneously hypertensive rats (SHR), which suggests that this subnucleus of the NTS is a source of sympathoexcitation. Exercise training reduces sympathetic activity and arterial pressure. The purpose of the present study was to investigate whether the swimming exercise can modify the regional vascular responses evoked by inhibition of the commNTS neurons in SHR and normotensive Wistar-Kyoto (WKY) rats.

Recovery of high blood pressure after chronic lesions of the commissural NTS in SHR.

Acute electrolytic lesions of the commissural nucleus of the solitary tract (commNTS) reduce blood pressure (BP) in SHR but not in normotensive Wistar-Kyoto and Wistar rats and abolish the pressor response to intravenous injection of potassium cyanide. We investigated the chronic effect of commNTS lesions on mean arterial pressure (MAP), and on baroreceptor and chemoreceptor reflex responses in SHR. The contribution of the sympathetic nervous system and the hormones vasopressin and angiotensin II to maintenance of BP in lesioned SHR was also investigated.