title: The selectivity of DG-5128 as an alpha 2-adrenoceptor antagonist.
abstract: DG-5128 (2-[2-(4,5-dihydro-1H-imidazol-2-yl)-1-phenylethyl]pyridine dihydrochloride sesquihydrate) at concentrations up to 10 microM inhibited [3H]clonidine binding more effectively than it did [3H]prazosin binding in rat cerebral cortex membranes. The mode of inhibition was homogeneous and consistent with the law of simple mass action. DG-5128 exhibited a 7.4 times higher affinity (pKi = 6.28) toward alpha 2-adrenoceptors than alpha 1-adrenoceptors. The results indicate that DG-5128 is a preferential alpha 2-antagonist.
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism; D003000:Clonidine / Q000378:metabolism; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007093:Imidazoles / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D011224:Prazosin / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000317:Adrenergic alpha-Antagonists; D007004:Hypoglycemic Agents; D007093:Imidazoles; C032368:midaglizole; D003000:Clonidine; D011224:Prazosin