Roles of Central Renin-angiotensin System and Afferent Renal Nerve in the Control of Systemic Hemodynamics in Rats

Afferent renal nerves (ARNs) convey signals generated by physiological changes in the kidney to the central nervous system. The aim of this study was to determine whether ARNs contribute to cardiovascular regulation through central renin-angiotensin system (RAS)-dependent pathways. Blood pressure and renal sympathetic nerve activity (RSNA) were monitored during elevations in pelvic pressure in anesthetized Wistar-Kyoto Izm (WKY) rats and spontaneously hypertensive Izm rats (SHRs). In both groups of rats, blood pressure and RSNA were significantly increased in response to elevations in renal pelvic pressure in a pressure-dependent fashion, which were prevented by renal denervation. Injection of an angiotensin II type I receptor blocker (CV-11974, 10 μg) into the intracerebroventricular region significantly suppressed the vasopressor and sympathoexcitatory responses to the increases in pelvic pressure in both WKY rats and SHRs, although these inhibitory effects of CV-11974 in SHRs appeared to be weaker than in WKY rats. These results indicate that signals transmitted by ARNs have an important role in the control of systemic hemodynamics through regulating central RAS-mediated changes in sympathetic nerve activity.