Investigation of reflexes from volume and baroreceptors during converting-enzyme inhibition in humans.

This article emphasizes the importance of testing baroreceptor and cardiopulmonary receptor control of circulation during angiotensin-converting enzyme (ACE) inhibitor treatment in hypertensives, because removal of angiotensin II-dependent stimulation of the sympathetic nervous system could impair reflex blood pressure homeostasis. In essential hypertensive subjects, the sympathetic vasoconstriction that occurs in skeletal muscle after deactivation of cardiopulmonary receptors was reduced after short-term or prolonged administration of the ACE inhibitor, captopril. However, another sympathetic target of the cardiopulmonary reflex, that is, renin release, was unaltered by both short-term and prolonged administration of captopril. Furthermore, the blood pressure and heart rate influences of arterial baroreceptors were preserved or even enhanced after administration of captopril. Thus important reflex mechanisms for cardiovascular homeostasis are not adversely affected by ACE inhibition, which preserves blood pressure levels during gravity challenges or exercise. Preliminary data suggest that this may be even more evident for benazepril.