Reduction of Dopamine Receptor Activity Differentially Alters Striatal Neuropeptide mRNA Levels

Abstract
We have investigated the effect of dopamine receptor blockade on striatal proenkephalin mRNA and protachykinin mRNA by Northern gel analysis and by in situ hybridization histochemistry. Chronic haloperidol treatment resulted in a 3.5 fold increase in striatal proenkephalin mRNA and a 30% decrease in protachykinin mRNA (no apparent change in α-tubulin mRNA was observed). The changes in mRNA levels for protachykinin and proenkephalin were uniform throughout the caudate-putamen of the rat as determined by in situ hybridization histochemistry. The results imply that altering receptor-mediated neurotransmitter functions can lead to profound, specific, and long-lasting alterations in neuronal gene expression.