Effect of amitraz on intestinal contractility

Shin, Dong-ho; Lim, Chae-mi; Kim, Jae-ha

Korean Journal of Veterinary Research 1995;35(2):255-261.

Dong-ho Shin¹, Chae-mi Lim¹, Jae-ha Kim²

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

장평활근의 수축성에 대한 amitraz의 영향

신동호¹, 임채미¹, 김재하²

¹전남대학교 수의과대학
²전남대학교 의과대학

Abstract

Amitraz frequently causes the side effect of intestinal stasis or bloat in mammals. It is very similar to the side effect of xylazine or clonidine which produce the inhibition of intestinal motility through the stimulation of ${alpha}_2$ adrenoceptor. Therefore, we examined whether amitraz causes intestinal stasis or bloat through the inhibition of intestinal motility or whether amitraz produces the inhibition of intestinal motility through the stimulation of ${alpha}_2$ adrenopceptor. Amitraz inhibited the intestinal motility in a dose-dependent manner in isolated rabbit jejunum and isolated pig ileum. These inhibitory effects of amitraz were blocked by yohimbine but not by prazosin. The effect of intestinal contraction of carbachol or high-potassium was not affected by the pretreatment of amitraz. However, the con-traction of histamine was inhibited by the pretreatment of amitraz. It is concluded that amitraz mainly inhibits the intestinal motility through the stimulation of ${alpha}_2$-adrenoceptor although partially antihistaminic action of amitraz can be involved.

Key Words: amitraz, ${alpha}_2$-adrenoceptor, isolated intestinal segment