ENDOTHELIUM-DEPENDENT CONTRACTION INDUCED BY ACETYLCHOLINE IN ISOLATED RAT RENAL-ARTERIES

We investigated whether or not acetylcholine elicited an endothelium-dependent contraction and whether an arachidonic acid metabolite was involved in the acetylcholine-induced contraction in ring preparations of rat renal arteries. Acetylcholine (0.1-100 mu M) caused a transient contraction in endothelium-intact arteries in a concentration-dependent manner. The contraction induced by acetylcholine (10 mu M) was enhanced by pretreatment with N-G-nitro-L-arginine (100 mu M), a nitric oxide synthase inhibitor, and was abolished by mechanical removal of the endothelium. Atropine (0.1 mu M), quinacrine (1 and 3 mu M), manoalide (0.1 and 1 mu M), aspirin (1 and 10 mu M), indomethacin (30 and 300 nM), ONO-3708 (9,11-dimethyl-methane-11,12-methano-13,14-dihydro-13-aza-14-oxo-15(beta)-cyclophenyl-omega-pentenor-thromboxane A(2) L-arginine salt) (10 nM), S-1452 (calcium (5Z)-1R,2S,3S,4S-7-[3-phenylsulphonyl-aminobicyclo[2.2.1]hept-2yl]-5-heptenoate hydrate) (3 nM) and SQ29,548 ([1S- [1 alpha,2 beta(5Z),3 beta,4 alpha]]-7-[3-[[2-[(phenylamino) carbonyl]hydrazino]methyl]-7-oxabicyclo[2.2.1]hept-2-yl]-5-heptenoic acid) (3 and 10 nM), but not hexamethonium (1 mu M), OKY-046 (sodium (E)-3-[4-(1-imidazolylmethyl)phenyl]-2-propenoic acid hydrochloride monohydrate) (100 mu M) and CS-518 (sodium 2-(1-imidazolylmethyl)-4,5-dihydrabenzo[b]thiophene-6-carboxylate) (10 mu M) significantly attenuated the acetylcholine (10 mu M)-induced endothelium-dependent contractions in renal arteries pretreated with N-G-nitro-L-arginine. These findings suggest that acetylcholine causes endothelium-dependent contraction by stimulation of muscarinic receptors in rat renal arteries, and that an arachidonic acid metabolite(s) of the cyclooxygenase pathway is involved in this endothelium-dependent contraction.