Swimming Exercise Changes Hemodynamic Responses Evoked by Blockade of Excitatory Amino Receptors in the Rostral Ventrolateral Medulla in Spontaneously Hypertensive Rats

• Published in: BioMed research international 2014-01, Vol.2014 (2014), p.1-9
• Main Authors: Ogihara, Cristiana A., Schoorlemmer, Gerhardus H. M., Lazari, Maria de Fátima M., Giannocco, Gisele, Lopes, Oswaldo U., Colombari, Eduardo, Sato, Monica A.
• Format: Article
• Language: English
• Subjects: Animals; Aquatic exercises; Blood pressure; Blood Pressure - drug effects; Brain research; Cardiovascular System - drug effects; Glutamic Acid - pharmacology; Health aspects; Heart Rate - drug effects; Hemodynamics - drug effects; Hypertension; Kynurenic Acid - pharmacology; Medulla Oblongata - drug effects; Medulla Oblongata - physiology; Nitric oxide; Nitric Oxide - metabolism; Physical Conditioning, Animal; Rats, Inbred SHR; Rats, Inbred WKY; Receptors, Glutamate - metabolism; Rodents; Studies; Swimming
• ISSN: 2314-6133; 2314-6141
• DOI: 10.1155/2014/487129

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. Rats were α-chloralose anesthetized and artificially ventilated, with Doppler flow probes around the lower abdominal aorta and superior mesenteric artery. Injections into the RVLM were made before and after i.v. L-NAME (nitric oxide synthase, NOS, inhibitor). Injections of KYN into the RVLM elicited a major vasodilation in the hindlimb more than in the mesenteric artery in E-SHR compared to S-SHR, but similar decrease in arterial pressure was observed in both groups. Injections of KYN into the RVLM after i.v. L-NAME attenuated the hindlimb vasodilation evoked by KYN and increased the mesenteric vasodilation in E-SHR. Swimming exercise can enhance the hindlimb vasodilation mediated by peripheral NO release, reducing the activation of neurons with EAA receptors in the RVLM in SHR.