Striatal dopamine D1-like receptors have higher affinity for dopamine in ethanol-treated rats.

Experiments were carried out with brain tissues of ethanol-experienced (long-term ethanol intake but withdrawn) vs. ethanol-naive animals. The in vitro 3H antagonist binding of [3H]SCH 23390 and of [3H]spiperone to striatal dopamine D1- and D2-like receptors revealed no significant changes in KD and Bmax values. Displacement of the 3H antagonist binding by dopamine indicated high- and low-affinity states, which also showed no significant alteration at the D2-like receptor but a 5-fold increase of dopamine affinity at the high-affinity state of the D1-like receptor of the ethanol-experienced rats.