Impaired nitrergic relaxation of the sphincter of Oddi of hyperlipidaemic rabbits

Field stimulation relaxed the sphincter of Oddi muscle rings of the rabbit after incubation with phentolamine, oxprenolol and atropine (all 1 mu M). The relaxation was blocked by N-G-nitro-L-arginine methyl ester (30 mu M) and was reversed by 3 mM L-arginine but not D-arginine. Sphincter of Oddi preparations from hypercholesterolaemic rabbits exhibited contractions under the same conditions. We conclude that nitrergic relaxation is impaired in the sphincter of Oddi from hypercholesterotaemic rabbits.