title: Characterization of beta-adrenoceptors in the dog saphenous vein.
abstract: In vitro experiments were carried out on strips of the dog saphenous vein to characterize beta-adrenoceptors mediating relaxation. Four beta-adrenoceptor agonists, isoproterenol, salbutamol, procaterol and alpha-(3,4,5-trimethoxyphenethylaminomethyl)-3,4-dihydroxybenzylalcohol hydrochloride (T-1583), all produced concentration-dependent relaxation of venous strips contracted by 10(-6) M methoxamine. These four drugs behaved as full agonists. In producing venous relaxation, procaterol was about 2.5 times more potent, and salbutamol and T-1583 were 7 and 98 times less potent than isoproterenol, on a molar basis. The concentration-relaxation response curves to the four agonists were shifted in a parallel way to the right by (t-butyl-amino-3-ol-2-propyl)oximino-9 fluorene hydrochloride (IPS 339), a selective beta 2-adrenoceptor antagonist, and by practolol. However, pA2-values for IPS 339 against the four agonists were all nearly 11.0, whereas those for practolol were all nearly 5.7. We conclude that beta-adrenoceptors in the dog saphenous vein mediating relaxation are predominantly on the beta 2 type.
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D004285:Dogs; D004347:Drug Interactions; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008729:Methoxamine / Q000494:pharmacology; D009126:Muscle Relaxation / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011217:Practolol / Q000494:pharmacology; D011412:Propanolamines / Q000494:pharmacology; D011941:Receptors, Adrenergic / Q000187:drug effects*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D012501:Saphenous Vein / Q000187:drug effects*
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; C014898:IPS 339; D008729:Methoxamine; D011217:Practolol