Chronic administration of three neuroleptics: effects of behavioral supersensitivity mediated by two different brain...

This investigation assessed the relative abilities of three neuroleptics to supersensitize behaviors mediated by the nigrostriatal and mesolimbic dopamine (DA) systems. Rats were treated with either haloperidol, thioridazine, fluotracen or vehicle for 21 days. Stereotypy, in response to DA injection to the striatum, or locomotor activity, in response to DA injection to the nucleus accumbens, were measured after the termination of drug treatment. Pre-treatment with haloperidol enhanced both behavioral responses to central DA injection, while pre-treatment with thioridazine did not enhance either behavior. Pre-treatment with fluotracen enhanced the locomotor response to DA injection to the nucleus accumbens, but did not alter stereotypy after DA injection to the striatum. Neuroleptics differ in their ability to supersensitize the same DA-related behavior, and act selectively to supersensitize behaviors mediated by different DA systems.