Continuous treatment with the D2 dopamine receptor agonist quinpirole decreases D2 dopamine receptors, D2 dopamine receptor messenger RNA and proenkephalin messenger RNA, and increases mu opioid receptors in mouse striatum

摘要: Dopamine-mediated behaviors and certain biochemical molecular events associated with these were examined following continuous infusion of the D1 dopamine agonist SKF38393 or D2 quinpirole into mice for six days. produced a transient grooming behavior while initially induced stereotypy, which was followed by an increased locomotor behavior. Continuous caused significant down-regulation striatal receptors without significantly changing density receptors. This accompanied decrease in level receptor messenger RNA striatum as measured Northern analysis. The selective receptors, since treatment had no effects on either nor did it alter RNAs resulted increase mu opioid levels delta also proenkephalin striatum. Taken together, results suggest that is result persistent stimulation up-regulation may be compensatory response to decreased biosynthesis enkephalin. They further changes take place dopaminergic enkephalinergic systems agonists underlie mechanisms dopamine-mediated occur.