title: 5-Methyl-urapidil discriminates between subtypes of the alpha 1-adrenoceptor.
abstract: The affinity of 5-methyl-urapidil for alpha 1-adrenoceptors was determined from the inhibition of [3H]prazosin binding on membrane of different rat tissues. In hippocampus, vas deferens and heart 5-methyl-urapidil displaced [3H]prazosin in a biphasic manner with mean pKI values between 9.1 and 9.4 for the high-affinity site and 7.2 to 7.8 for the low-affinity site. Only the low affinity site was found in spleen and liver. At present, 5-methyl-urapidil is the antagonist which most clearly discriminates between alpha 1-adrenoceptor subtypes.
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000378:metabolism / Q000493:pharmacokinetics; D000818:Animals; D001665:Binding Sites; D001667:Binding, Competitive; D066298:In Vitro Techniques; D008297:Male; D010879:Piperazines / Q000378:metabolism* / Q000493:pharmacokinetics; D011224:Prazosin / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D000317:Adrenergic alpha-Antagonists; D010879:Piperazines; D011942:Receptors, Adrenergic, alpha; C057446:5-methylurapidil; D011224:Prazosin