COMPARISON OF SENSITIZATION ELICITED BY AMPHETAMINE AND PERTUSSIS TOXIN - CHARACTERIZATION OF LOCOMOTOR BEHAVIOR AND LIMBIC DOPAMINE RELEASE

1. Male, Sprague-Dawley rats were pretreated with one of several regim ens of repeated, intermittent amphetamine or with a single-dose of int ra-VTA pertussis toxin (PTX). 2. An amphetamine challenge dose (0.5 mg /kg, i.p.) produced increased locomotor activity in both amphetamine a nd pertussis toxin-pretreated rats. 3. The magnitude of activity in PT X pretreated rats exceeded 5-fold that of the amphetamine-pretreated r ats. 4. There were no significant differences in the levels of sensiti zed behavior elicited by 4 distinct amphetamine pretreatment protocols . 5. Neither of the drug pretreatments caused significant changes in t he ability of 10 mu M amphetamine to promote dopamine efflux from nucl eus accumbens or striatal tissue in vitro. 6. The sensitized behavior cannot be explained by in vitro alterations in pre-synaptic dopamine r elease, which may suggest an up-regulation of post-synaptic activity.