Renal nerve activity and exaggerated natriuresis in conscious spontaneously hypertensive rats.

摘要: Exaggerated natriuresis upon volume loading occurs in both human and animal hypertension is mainly due to suppressed tubular reabsorption. To explore whether altered renal sympathetic activity contributes this response, conscious male spontaneously hypertensive rats (SHR) were exposed isotonic saline comparison with normotensive Wistar Kyoto (WKR). After a 60 min control hydropenic period, during which mean arterial pressure, heart rate, nerve urinary sodium excretion followed, period of intravenous expansion (0.2 ml/min X 100 g b.w.) was started followed by recovery period. Already the significantly higher SHR. During load subsequent clearly exaggerated occurred SHR compared WKR. Further, reduced all animals, but more Moreover, pressure rate groups. It suggested that accentuated reflex inhibition emanates from cardiac mechanoreceptors partly explains This augmented "volume' response probably systemic venous compliance consequently increased central filling receptor activation.