Effects of catecholamines on the smooth muscle strips of the cattle oesophageal groove

Cho, Je-yoel; Yang, Il-suk

Korean Journal of Veterinary Research 1991;31(2):171-178.

Je-yoel Cho, Il-suk Yang

College of Veterinary Medicine, Seoul National University

소(우(牛))의 식도구 평활근 절편에 대한 catecholamine의 작용

조제열, 양일석

서울대학교 수의과대학

Abstract

Effects of catecholamines were investigated on isolated strips of the male cattle oesophageal groove. In the circular muscles of the bottom and longitudinal muscles of the lip. isometric tensions was recorded with isometric myograph in 25ml organ bath. The results were as follows: 1. The muscular activity was different in preparations from the two parts. In the longitudinal muscle from the lip, rhythmic contractions generally occurred. while in the circular muscle from the bottom they were not seen almost. 2. In the circular muscle of the bottom, the increased tone and biphasic contractions were caused by catecholamines. And these contractions were mediated through $alpha$-excitatory adrenoceptor. Also circular muscle showed minor inhibitory response to catecholamines. And these effects were mediated through $eta$-inhibitory adrenoceptor. But the circular muscle was more sensitive to the $alpha$-excitatory effect than $eta$-inhibitory effect. 3. In logitudinal muslce of the lip. rhythmic contractions were reduced or disappeared by catecholamines(especially propranolol) and these effects were mediated through $eta$-adrenoceptor.

Key Words: oesophageal groove, catecholamine, adrenoceptor, smooth muscle, ruminant