Behavioral and biochemical effects of subchronic treatment with (-)3-(3-hydroxyphenyl)-N-n-propylpiperidine in the rat: dopamine receptor sensitivity and tolerance.

Male Sprague-Dawley rats were treated for 3 weeks with (-)3-(3-hydroxyphenyl)-N-n-propylpiperidine (3-PPP). Twenty-four hours, but not 72 hours, after withdrawal of the treatment there was an increase in locomotor activity in comparison with saline treated controls. At the same time there was a decrease in striatal DOPAC and HVA and an increased locomotor activity response to apomorphine, indicating supersensitive dopamine receptors. There was no evidence for behavioral tolerance since the suppression of locomotor activity after an acute dose of (-)3-PPP was the same in (-)3-PPP-pretreated as in saline-treated controls. Plasma levels of (-)3-PPP in these animals were, however, slightly decreased.