Article date: 1989/9/4
PubMed ID: 2804645
Journal name: Brain research (ISSN: 0006-8993)
The action of phaclofen, the phosphonic acid derivative of baclofen, on baclofen-induced suppression of spinal reflex transmission was tested in anaesthetized rats. Intrathecal (i.th.) injection of phaclofen, 100 nmol, antagonized the depressant effect of baclofen, 2 nmol, on spinal Hoffmann (H)-reflexes and polysynaptic flexor reflexes but ha on the action of muscimol, 20 nmol. The antagonistic effect of phaclofen on baclofen-induced depression of H-reflexes was dose-dependent in doses ranging from 1 to 100 nmol. When administered alone, phaclofen, 100 nmol, was devoid of stimulatory or depressant effects on spinal reflexes. These results indicate that phaclofen specifically antagonizes the reflex suppressant action of baclofen. The lack of intrinsic action of phaclofen suggests that there is no endogenous tonic inhibition mediated by GABAB receptors under the present experimental conditions.
Author List: Wüllner U, Klockgether T, Sontag K H
Publication Types: Journal Article; Research Support, Non-U.S. Gov't
Substances mentioned in the article: phaclofen; Baclofen;
Mesh terms: Animals; Baclofen/analogs & derivatives; H-Reflex/drug effects; Male; Neural Inhibition/drug effects; Rats; Rats, Inbred Strains; Reflex, Monosynaptic; Spinal Cord/drug effects;