| Description: |
Atipamezole Hcl(MPV1248 Hcl) is an alpha-adrenoceptor antagonist with high affinity and selectivity for the alpha 2-receptor.in vitro: The alpha2-adrenoceptor antagonist atipamezole was a potent inhibitor of aldosterone release (range 10-1000 nM). In receptor binding studies [( 3H]-clonidine and [3H]-prazosin displacement) an alpha 2/alpha 1 selectivity ratio of 8526 was obtained for atipamezole, while idazoxan and yohimbine showed ratios of 27 and 40, respectively. Atipamezole had also about a 100 times higher affinity on alpha 2-adrenoceptors than the reference compounds.
in vivo: In vivo studies of [3H]atipamezole demonstrated good penetration into the brain (0.3-1.8% injected dose/g at 5 min, depending upon brain region). In addition, [3H]atipamezole displayed rapid in vivo clearance of nonspecific binding such that at 1 h following an i.v. injection of the drug (100 microCi/animal, rat tail vein administration) the pattern of radioactivity in the brain correlated very well with the receptor distribution as seen by in vitro autoradiography. In mice, medetomidine-induced sedation was effectively antagonized by atipamezole. |
