EVIDENCE FOR SUPRASPINAL NERVOUS CONTROL OF EXTERNAL ANAL-SPHINCTER MOTILITY IN THE CAT

Citation
A. Abysique et al., EVIDENCE FOR SUPRASPINAL NERVOUS CONTROL OF EXTERNAL ANAL-SPHINCTER MOTILITY IN THE CAT, Brain research, 795(1-2), 1998, pp. 147-156
Citations number
52
Categorie Soggetti
Neurosciences
Journal title
ISSN journal
00068993
Volume
795
Issue
1-2
Year of publication
1998
Pages
147 - 156
Database
ISI
SICI code
0006-8993(1998)795:1-2<147:EFSNCO>2.0.ZU;2-W
Abstract
The aim of this study was to investigate the role of noradrenergic des cending nervous pathways in external anal sphincter motility. For this purpose, the effects of intravenously injected adrenoceptor antagonis t and agonist on the tonic electrical activity of this sphincter were studied in anesthetized cats. The effects of stimulating the region of the locus coeruleus and the effects of intravenous, intracerebroventr icular and intrathecal injection of the above drugs on the electromyog raphic responses of this muscle to pudendal nerve stimulation were als o investigated. The tonic sphincteric activity and the reflex response triggered by electrically stimulating pudendal afferent nerve fibers were inhibited by alpha(1)-adrenoceptor antagonist nicergoline and enh anced by alpha(1)-adrenoceptor agonist phenylephrine. Stimulation of t he locus coeruleus area either inhibited or enhanced the reflex respon ses. Intracerebroventricular and intrathecal injection of the alpha(1) -adrenoceptor agonists, morphine and leu-enkephalin decreased the ampl itude of these reflex responses. All the effects of opioids were block ed by naloxone and by spinalization performed at the cervical and lumb ar levels. The direct response elicited by stimulating the sphincteric motor axons was not affected either by these drugs or by the brainste m stimulation. These results suggests the existence of a pontine neuro nal network controlling the motility of the external anal sphincter vi a noradrenergic and opioid neurons. (C) 1998 Elsevier Science B.V. All rights reserved.