5-hydroxytryptamine desensitization fails to modify GABA-induced inhibitory responses in the guinea-pig colon.
In segments of guinea-pig colon, treated with 1 microM hyoscine, a 5-HT desensitization procedure that decreased the potency of 5-HT 41-fold in relaxing the longitudinal musculature, failed to modify the non-adrenergic GABA-induced inhibitory responses, suggesting that the action of GABA in this preparation is not 5-HT-mediated. These results are at variance with those obtained in the guinea-pig ileum where 5-HT seems to play a role in GABA-induced cholinergic contractions.
D000818:Animals; D003106:Colon / Q000187:drug effects; D004347:Drug Interactions; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects*; D012701:Serotonin / Q000494:pharmacology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D012701:Serotonin; D005680:gamma-Aminobutyric Acid