Antiparkinsonian activity of (+)-PHNO in the MPTP-treated common marmoset.

Administration of MPTP (1-4 mg/kg ip daily for 5-7 days) to common marmosets induced persistent parkinsonian motor deficits. The subcutaneous administration of (+)-PHNO [(+)-4-propyl-9-hydroxynaphthoxazine; 1-4 micrograms/kg] caused a dose-dependent reversal of the akinesia and incoordination of movement. Similarly, oral administration of (+)-PHNO (5-20 micrograms/kg) caused an equivalent reversal of the motor abnormalities. No dyskinetic phenomena were induced by (+)-PHNO on oral or subcutaneous administration. Oral or subcutaneous administration of (+)-PHNO to normal control marmosets also increased the usual repetoire of motor behaviour, but this was not as marked as in MPTP-treated animals. (+)-PHNO is a potent dopamine agonist drug of potential use in the treatment of Parkinson's disease.