ACETYLCHOLINE-INDUCED VASODILATATION IN THE HUMAN HYPERTENSIVE KIDNEY- INHIBITION BY MUSCARINIC RECEPTOR ANTAGONISM

Objective To evaluate the vascular response of the human hypertensive kidney to endothelial stimulation with acetylcholine (ACh) and to asse ss whether this effect can be inhibited by the non-specific muscarinic receptor antagonist atropine. Patients and methods Three stepwise inc reasing doses of ACh (0.3, 1.0 and 3.0 mu g/kg per min) in combination either with placebo or with 100 or 300 ng/kg per min atropine were in fused into the right renal artery of 20 hypertensive patients. Renal b lood flow was determined using the 133Xe wash-out technique. Results I nfusion of ACh induced a dose-dependent increase in renal blood flow ( P = 0.02). Both doses of atropine attenuated the ACh-induced renal vas odilatation (P < 0.05). Conclusions Administration of ACh to the human hypertensive kidney induces a dose-dependent increase in renal blood flow. This effect is, at least partially, mediated by muscarinic recep tors. (C) Rapid Science Publishers ISSN 0263-6352.