Neonatal dopamine depletions spare lateral hypothalamic stimulation reward in adult rats

Previous research has shown that adult rats sustaining near-total depletions of striatal dopamine (DA) as neonates exhibit few of the profound deficits in ingestion and sensory-motor behavior seen in comparably lesioned adults. This study extends these findings to another realm of DA-related behavior, reward function. In a rate-frequency curve-shift measurement paradigm, reward effectiveness of lateral hypothalamic brain stimulation was shown to be normal in adult rats depleted of brain DA as neonates. However, impairments were seen in rapid-initiation operant performance. Neonatally DA-depleted rats were also shown to be subsensitive to the DA receptor antagonist pimozide, suggesting that activity within undamaged DA neurons is not necessary for the elicitation of hypothalamic self-stimulation reward.