STRIATAL SYNAPTOPHYSIN EXPRESSION AND HALOPERIDOL-INDUCED SYNAPTIC PLASTICITY

SYNAPTOPHYSIN is a presynaptic vesicle protein and a marker of synapti c density. We have studied the expression of its encoding mRNA in the brains of rats treated with haloperidol (2 mg kg-1 d-1) for two weeks. A significant increase in synaptophysin mRNA content was observed in the dorsolateral striatum but not in other brain areas compared with c ontrol animals. A similar trend was observed for synaptophysin immunor eactivity. Quantification of synaptophysin mRNA per cell showed that t he increase was pronounced in large putatively cholinergic, striatal n eurones. These data provide further evidence that localized synaptic p lasticity occurs after neuroleptic treatment and indicate that such al terations are manifested in terms of expression of a synaptic protein gene by striatal neurones.