Comparison of GABA-induced responses in various segments of the guinea-pig intestine.
In preloaded, isolated segments of duodenum, jejunum, ileum and colon, ethylenediamine (EDA) caused a 3-mercaptopropionic acid (3-MPA)-sensitive release of [3H]GABA. Both EDA and GABA caused a contraction and a delayed 'after-relaxation' in the ileum, but only a delta-aminovaleric acid (DAVA)-sensitive relaxation in other intestinal segments; these actions of EDA were reduced by 3-MPA and therefore due to release of endogenous GABA. Baclofen induced a DAVA-sensitive relaxation in all tissues. Evidently, GABA modulates cholinergic excitation of the smooth muscle at all levels of the intestine.
D000818:Animals; D005029:Ethylenediamines / Q000494:pharmacology; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007422:Intestines / Q000187:drug effects; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D011963:Receptors, GABA-A / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D005029:Ethylenediamines; D011963:Receptors, GABA-A; D005680:gamma-Aminobutyric Acid