A tripeptide with diverse biological activities; binds to rat striatum (Kd = 4.69 nM); decreases immobility of mice in the forced swim test (0.1 mg/kg); increases striatal concentrations of dopamine, DOPAC, 3-MT, and HVA in a mouse model of Parkinson's disease (20 mg/kg); decreases haloperidol-induced vacuous chewing in a rat model of tardive dyskinesia (2 mg/kg); reverses morphine- and enkephalin-induced analgesia in mice in a radiant heat tail-flick assay ,