Behavioral and biochemical expression of D1-receptor supersensitivity following SCH 23390 repeated administrations.

In this study concomitant changes of behavioral and biochemical responses in rats repeatedly treated with SCH 23390 were evaluated. Apomorphine-induced stereotyped behavior was increased in D1-supersensitive rats, in contrast no change in the behavioral response to the pure D1-agonist SKF 38393 was detected. Parallel biochemical studies indicated that the enhancement in striatal dopamine (DA) metabolite concentration due to the administration of spiroperidol plus SKF 38393 was not potentiated in SCH 23390 repeatedly treated rats. The results show that the expression of D1-supersensitivity could depend on the stimulation of D2-receptors.