Effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine on striatal dopamine receptors in C57BL/6 mice

The effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a neurotoxin which selectively destroys the nigrostriatal dopaminergic neurons and produces Parkinson's disease-like syndrome, on striatal dopamine receptors was determined in a mouse strain known to be very sensitive to the neurotoxic effect of MPTP. Daily intraperitoneal administration of MPTP (30 mg/kg) for 7 days to male C57BL/6 mice reduced the concentration of striatal dopamine by 90%. This decrease in dopamine concentration was not associated with changes either in the receptor density (Bmax) or the apparent dissociation constant (Kd) of [3H]spiroperidol to bind to striatal dopamine receptors. It is concluded that in spite of large decrease in striatal dopamine concentration by MPTP the dopamine receptors labeled with [3H]spiroperidol remain intact.