Hemodynamics of experimentally hypertensive rats in conscious and anesthetized states

Cardiac output was measured by a pulse contour method in reno-vascular hypertensive rats, deoxycorticosterone (DOC) hypertensive rats and normotensive control Wistar rats in the conscious state. All rats were male in sex and 12-13 weeks of age (2-3 weeks after operation in the hypertensive rats). Cardiac output per body weight was not significantly different among the groups. Therefore, the hypertension in the experimentally hypertensive rats in the conscious state was ascribable to an increased total peripheral resistance. After anesthesia with pentobarbital and thoracotomy, the DOC rats were no longer hypertensive. However, in the renovascular hypertensive rats, the hypertensive state due to an increase in vascular resistance persisted after anesthesia, thoracotomy, and even ganglion blockade with hexamethonium bromide, indicating the importance of non-neural factors in the renovascular hypertension. Aortic compliance measured in vivo under anesthesia was smaller in either the renovascular or DOC hypertensive rats than in the control rats before and after ganglion blockade, which suggests a non-neural hardening of elastic vessels in the experimental hypertensions.