Johnson B J, Peacock V, Schneider J S
Department of Neurology, Hahnemann University, Philadelphia, PA 19102, USA.
Pharmacol Biochem Behav. 1995 Aug;51(4):617-22. doi: 10.1016/0091-3057(94)00424-h.
Dihydrexidine (trans-10,11-dihydroxy5,6,6a,7,8,12b hexanhyydrobenso- [alpha]phenanthridine) is a full dopamine D1 agonist. In rhesus macaque monkeys rendered hemiparkinsonian by unilateral intracarotid infusions of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), dihydrexidine (0.15-0.9 mg/kg) elicited dose-dependent contralateral rotation. The effects of dihydrexidine were blocked by pretreatment with the D1 antagonist SCH 23390 (0.03 mg/kg), but not by the D2 antagonist raclopride (0.025 mg/kg). These results suggest a functional role for D1 receptors in stimulating motor behavior in a primate model of Parkinson's disease.
