Pretreatment with nimodipine prevents MPTP-induced neurotoxicity at the nigral, but not at the striatal level in mice

The present study assessed the effects of pretreatment with the calcium-L-type channel blocker nimodipine on biochemical and histological parameters of systemic MPTP-induced (2 x 40 mg kg-1 body weight subcutaneously, 16 h apart), dopaminergic neurotoxicity in black C57BL/6 mice. Continuous administration of nimodipine via subcutaneously implanted pellets (10 mg), starting 7 days before administration of MPTP, did not antagonize the striatal MPTP-induced dopamine depletion (caudate-putamen: 80% of control; nucleus accumbens; 25% of control), but almost completely prevented the MPTP-induced tyrosine hydroxylase immunoreactive-cell loss in the substantia nigra (20% of control) 7 days after administration of MPTP. This data suggests that pretreatment with nimodipine--during the observation period of 7 days--protects against MPTP-induced neurotoxicity in mice at the nigral ('cell body'), but not at the synaptic striatal level.