Effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on dopamine synthesis and release in the rabbit retina in vitro.

The effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on the synthesis and release of dopamine (DA) was investigated in the retina of the rabbit in vitro. The results indicated that MPTP did not affect the synthesis of DA, but increased its release. Blockade of the activity of monoamine oxidase (MAO) with pargyline (100 microM) did not abolish the capacity of MPTP to release DA. Similarly, these pharmacological effects of MPTP were not dependent on the presence or absence of melanin.