title: Characterization of beta-adrenergic receptors in the rat vas deferens using [3H]-dihydroalprenolol binding.
abstract: The beta-adrenergic antagonist, [3H]-dihydroalprenolol ([3H] DHA), binds to membranes prepared from the rat vas deferens in a specific and saturable manner. Scatchard and Hill plot analysis indicates a single class of binding sites with no evidence of cooperative interactions. The specific binding sites have a high affinity (Kd = 0.3 nM) and a maximal occupancy estimated to be 460 fmoles [3H]-DHA bound/g wet tissue weight. Beta-adrenergic agonists and/or antagonists inhibit [3H]-DHA binding to rat vas deferens membranes in a stereospecific manner and with a relative order of potency expected for beta-adrenergic receptors of the beta2 subtype. The receptor affinities of various beta-adrenergic antagonists in the rat vas deferens determined using inhibition of [3H]-DHA binding correlated with their receptor affinities determined physiologically using antagonism of isoproterenol-induced inhibition of neurogenic contractions in-vitro.
mesh_terms: D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000526:Alprenolol / Q000031:analogs & derivatives*; D000818:Animals; D001667:Binding, Competitive; D004082:Dihydroalprenolol / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000187:drug effects / Q000378:metabolism*; D014649:Vas Deferens / Q000502:physiology*
chemical_list: D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011941:Receptors, Adrenergic; D011943:Receptors, Adrenergic, beta; D004082:Dihydroalprenolol; D000526:Alprenolol; D007545:Isoproterenol