title: Pre-junctional alpha 2-adrenoceptor activity of B-HT920.
abstract: An in-vitro study has been carried out on the pre-junctional alpha 2-adrenoceptor activity of the thiazoloazepine derivative B-HT 920 (6-allyl-2-amino-5,6,7,8-tetrahydro-4H-thiazolo[4,5-d]-azepine) using field-stimulated rat vas deferens and guinea-pig ileum. The alpha 2-selective agonists clonidine (an imidazoline derivative) and alpha-methyl noradrenaline (a beta-phenethylamine derivative) were compared. Results show that B-HT 920 is a potent agonist on pre-junctional alpha 2-adrenoceptors and is competitively antagonized by the selective alpha 2-adrenoceptor antagonist yohimbine. The characteristics of the pharmacological responses obtained with B-HT920 indicate that it interacts with the receptor in an imidazoline-like, rather than a beta-phenethylamine-like, manner.
mesh_terms: D000316:Adrenergic alpha-Agonists; D000818:Animals; D001381:Azepines / Q000494:pharmacology*; D003000:Clonidine / Q000494:pharmacology; D004146:Dioxanes / Q000494:pharmacology; D004347:Drug Interactions; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D015016:Yohimbine / Q000494:pharmacology
chemical_list: D000316:Adrenergic alpha-Agonists; D001381:Azepines; D004146:Dioxanes; D015016:Yohimbine; C024763:talipexole; C010654:(2-(2',6'-dimethoxy)phenoxyethylamino)methylbenzo-1,4-dioxane; D003000:Clonidine