Neuroprotective effects of alpha-dihydroergocryptine against damages in the substantia nigra caused by severe treatment with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine.

The effects on the substantia nigra of alpha-dihydroergocryptine (DEK), a drug with strong dopaminomimetic activity, were tested with a severe 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) treatment in monkeys. Compared with monkeys treated with MPTP alone, the animals which received DEK plus MPTP showed reduced neuronal death in the substantia nigra. The reactive astrocytes were increased in number. Moreover, several axons which were immunopositive to phosphorylated neurofilament proteins and with features similar to those of control animals were seen in the pars compacta. The findings suggest that DEK preserves neuronal morphology and brain architecture.