GABA-A-mediated gastrin release induced by baclofen in the isolated vascularly perfused rat stomach.
In order to investigate the role of peripheral GABA-B receptors, the effects of the putative GABA-B agonist baclofen on immunoreactive gastrin release from an isolated vascularly perfused rat stomach preparation were examined. The vascular infusion of baclofen at graded concentrations induced a dose-dependent increase in gastrin release; this was unaffected by the GABA-B antagonist delta-aminovaleric acid, but was fully prevented by the selective GABA-A antagonist bicuculline as well as by atropine or tetrodotoxin. These results suggest that the stimulant effects of baclofen are mediated by nervous cholinergic structures associated with GABA-A receptors, and indicate that this GABA-B agonist must be regarded as a partial agonist of peripheral GABA-A receptors.
Del Tacca
M
M
Institute of Medical Pharmacology, Veterinary Medical School, Pisa, Italy.
Blandizzi
C
C
Bernardini
M C
MC
Martelli
F
F
Della Longa
A
A
D000596:Amino Acids / Q000494:pharmacology; D021542:Amino Acids, Neutral; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001418:Baclofen / Q000494:pharmacology*; D001640:Bicuculline / Q000494:pharmacology; D005753:Gastric Mucosa / Q000187:drug effects / Q000378:metabolism*; D005755:Gastrins / Q000032:analysis / Q000378:metabolism*; D066298:In Vitro Techniques; D008297:Male; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D011963:Receptors, GABA-A / Q000378:metabolism*; D013779:Tetrodotoxin / Q000494:pharmacology
D000596:Amino Acids; D021542:Amino Acids, Neutral; D005755:Gastrins; D011963:Receptors, GABA-A; D013779:Tetrodotoxin; C013809:5-aminovaleric acid; D001285:Atropine; D001418:Baclofen; D001640:Bicuculline