We have studied the effects of ventral hippocampal lesion on mesolimbic dopamine system. Since some evidence exists that structural changes in the temporal limbic cortex in patients with schizophrenia may reflect a neurodevelopmental anomaly, we explored the effects of the lesion induced in neonatal rats on behavioral indices of dopaminergic system later in life. Our results revealed that exciotoxic lesion of the ventral hippocampus remains silent until puberty where upon it produces exaggerated behavioral responses to a novel environment and to d-amphetamine. Moreover, rats with neonatal lesions are hyperresponsive to stress. This effect was not present in rats with similar lesions induced in adulthood. In conclusion, we showed that neurodevelopmental events may play an important role in bringing the effects of the subtle structural dysfunction induced perinatally on dopamine mesolimbic circuitry after puberty. This finding may have important implication for our understanding of mechanisms underlying pathophysiology of schizophrenia.
