Non-adrenergic non-cholinergic relaxation and contraction in circular smooth muscle of bovine reticular groove

Kang, Tong-mook; Han, Ho-jae; Yang, Il-suk

Korean Journal of Veterinary Research 1995;35(2):279-285.

Tong-mook Kang¹, Ho-jae Han², Il-suk Yang¹

¹College of Veterinary Medicine, Seoul National University
²College of Veterinary Medicine, Chonnam National University

소(우(牛)) 식도구 윤상근의 비아드레날린 비콜린성 이완 및 수축

강동묵¹, 한호재², 양일석¹

¹서울대학교 수의과대학
²전남대학교 수의과대학

Abstract

To characterize non-adrenergic non-cholinergic(NANC) nerve mediated contractile responses in circular smooth muscle of bovine reticular groove, we investigated NANC relaxation and contraction induced by electric field stimulation to enteric nerves. In the presence of atropine($1{mu}M$) and guanethidine($50{mu}M$), electric field stimulation at frequency of 1 to 16Hz(square pulses, 0.5ms duration, 70V) evoked clear-cut relaxations through stimulations. Transient 'rebound contraction' was occured when the stimulus was switched off. All of the responses (relaxation and rebound contraction) were dose-dependently blocked by Nw-nitro-$_{small{L}}$-arginine methyl ester(L-NAME), an inhibitor of nitric oxide synthesis, and methylene blue, and inhibitor of soluble guanylate cyclase. Tetraethyl ammonium(TEA), a potassium channel blocker, did not block the NANC relaxations.

Key Words: bovine reticular groove, nitric oxide, NANC relaxation, rebound contraction, L-NAME