Poor interaction of some quinolizidine derivatives with dopamine D1- and D2- type receptors

The displacement of [3H]SCH-23390 and of [3H]spiperone from striatal, dopamine D1- and D2-type receptors by several quinolizidinyl-derivatives of bi- and tricyclic systems was investigated. All tested compounds did not affect SCH-23390 binding and exhibited only weak activity on spiperone binding to D2 binding sites (Ki = 1.9 microM). Therefore the good deconditioning activity (CAR blockade in rats) of 6-chloro-1-lupinyl-3-methyl-quinoxalinone (18) must rely on interactions with other kinds of receptors.