PSYCHOSTIMULANT-LIKE EFFECT OF CENTRAL MICROINJECTION OF NEUROTENSIN ON BRAIN-STIMULATION REWARD

The curve shift method and the brain stimulation reward paradigm were used to dissociate reward and performance changes and determine whethe r unilateral ICV microinjection of neurotensin (3, 10, and 30 mu g/10 mu l) produces neuroleptic- or psychostimulant-like effect on a dopami ne-dependent behavior. At the highest dose tested, neurotensin potenti ated brain stimulation reward, producing a significant time-dependent decrease in Frequency threshold. Neurotensin also suppressed maximal r are of responding at every dose tested, suggesting that it was more ef fective at attenuating performance capability. These results suggest t hat a centrally acting neurotensin receptor agonist may specifically s timulate dopamine-dependent behaviors. producing psychostimulant-like effect that can be attenuated or masked by a suppression of performanc e capability.