| Literature DB >> 1331912 |
M Tonini1, S A Waterman, S M Candura, T Coccini, M Costa.
Abstract
The effect of morphine on the ascending excitatory reflex of the circular muscle elicited by radial distension of the gut wall was studied in the isolated guinea-pig small intestine. A three compartment bath, in which an intermediate compartment divided the site of intraluminal stimulation (caudal compartment) from the site of reflex contraction recording (oral compartment), was used. Morphine (0.01-10 microM) applied independently to each compartment, caused a concentration-dependent depression (up to 90%) of the amplitude of distension-evoked reflex contractions. Concentration-response curves to morphine were shifted to the right by naloxone (30 nM) with an apparent pA2 value of about 8.5, which suggests an interaction with opioid mu-receptor subtypes. Our results indicate that morphine not only depressed transmission from excitatory motor neurons to the circular muscle but also neuro-neuronal transmission along the ascending excitatory reflex pathway.Entities:
Mesh：
Substances：
Year: 1992 PMID： 1331912 DOI： 10.1016/0304-3940(92)90748-v
Source DB: PubMed Journal: Neurosci Lett ISSN： 0304-3940 Impact factor: 3.046