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 assess whether this effect can be inhibited by the non-specific muscarinic receptor antagonist atropine.


METHODS
Three stepwise increasing doses of ACh (0.3, 1.0 and 3.0 microg/kg per min) in combination either with placebo or with 100 or 300 ng/kg per min atropine were infused into the right renal artery of 20 hypertensive patients. Renal blood flow was determined using the 133Xe wash-out technique.


RESULTS
Infusion of ACh induced a dose-dependent increase in renal blood flow (P= 0.02). Both doses of atropine attenuated the ACh-induced renal vasodilatation (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 receptors.
Wierema
T K
TK
Department of Internal Medicine, University Hospital Maastricht, The Netherlands.
Houben
A J
AJ
de Leeuw
P W
PW
D000109:Acetylcholine / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000328:Adult; D001285:Atropine / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D005260:Female; D006801:Humans; D006977:Hypertension, Renal / Q000503:physiopathology*; D007261:Infusions, Intra-Arterial; D007668:Kidney / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D018727:Muscarinic Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D011976:Receptors, Muscarinic / Q000502:physiology; D012079:Renal Circulation / Q000502:physiology*; D014664:Vasodilation / Q000187:drug effects*
D004338:Drug Combinations; D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D001285:Atropine; D000109:Acetylcholine