Journal of Neuroscience, Vol 9, 3665-3672, Copyright © 1989 by Society for Neuroscience
The neurotoxicity of 1-methyl-4-phenylpyridinium in cultured cerebellar granule cells
AM Marini, JP Schwartz and IJ Kopin
Clinical Neurosciences Branch, National Institutes of Neurological Disorders and Stroke, Bethesda, Maryland 20892.
Cerebellar granule cells in enriched primary culture are susceptible to the
neurotoxic effects of 1-methyl-4-phenylpyridinium (MPP+). Relatively high
MPP+ concentrations are required to elicit neurotoxic effects at early
culture times, but lower concentrations of MPP+ produce comparable
neurotoxic effects at later culture times. Under identical culture
conditions 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine (MPTP) is not
neurotoxic. Preincubation with the glutamate uptake blockers,
DL-threo-3-hydroxyaspartic acid or dihydrokainate, or the dopaminergic
uptake blocker mazindol, protects the granule cells from the cytotoxic
effects of MPP+. Although MPTP is not neurotoxic in an enriched granule
cell culture, in coculture with cerebellar astrocytes MPTP is toxic to
granule cells, presumably because it is converted in astrocytes to MPP+.
Cerebellar astrocytes remain confluent and viable. The addition of
pargyline to the coculture abolishes the neurotoxicity consistent with a
role of MAO B in bioactivation of MPTP. The concentration of MPP+ in the
coculture medium (13 microM) was less than that required for the toxic
effect in enriched neuronal cultures at earlier culture times, suggesting
that an astroglial-neuronal interaction, perhaps by proximity, enhances the
neurotoxicity of MPP+. These results might explain reported effects of MPTP
on some cerebellar cells in mice.