Narrowing in on compulsions: Dopamine receptor functions.

A series of experiments in rats explored the possibility that D3/D2 dopamine receptors are involved in behaviors that might be related to compulsion. A series of D3/D2 agonists and antagonists were shown to elicit yawning (D3-receptor mediated) and its inhibition (D2-receptor mediated). In rats with histories of cocaine exposure, D3-agonist-elicited yawning was enhanced, and quinpirole led to persistent operant responding only if conditioned stimuli associated with cocaine were presented for responding. Finally, a more selective D3 partial agonist was reported that had a novel profile of activity that could have relevance to the suppression of dopamine-related compulsions.