Article date: 1986/9/1
PubMed ID: 3025977
Journal name: Revista espanola de fisiologia (ISSN: 0034-9402)
Electric stimulation of the rat forepaw evokes a negative potential (N-wave) at the ipsilateral cuneate nucleus. The responses of the N-wave to microiontophoretically applied GABA agonists and antagonists have been studied. Applications of GABA-A agonists (3-amino-propanesulfonic acid and muscimol) reduce the amplitude of the N-wave. This effect decreases during prolonged application, suggesting a desensitization of GABA-A receptors. In addition the effect of muscimol is reduced by (-)-bicuculline methiodide. Baclofen (a GABA-B agonist) also depresses the N-wave but its action lasts longer, is less reversible, shows no desensitization and is not blocked by (-)-bicuculline methiodide. The different responses of the N-wave to GABA-A and GABA-B agonists are compatible with the existence of different types of functional receptors for them in the cuneate nucleus of the rat. The receptors activated by muscimol (GABA-A) are clearly not the same as the ones activated by baclofen (conceivably GABA-B).
Author List: Orviz P, Cecchini B G, Andrés-Trelles F
Publication Types: Journal Article; Research Support, Non-U.S. Gov't
Substances mentioned in the article: Receptors, GABA-A; Taurine; Muscimol; tramiprosate; Baclofen;
Mesh terms: Animals; Baclofen/pharmacology; Electric Stimulation; Evoked Potentials; Male; Medulla Oblongata/physiology; Muscimol/pharmacology; Rats; Rats, Inbred Strains; Receptors, GABA-A/drug effects; Taurine/analogs & derivatives;