Selegiline protects dopaminergic neurons in culture from toxic factor(s) present in the cerebrospinal fluid of patients with Parkinson's disease.

The cerebrospinal fluid (CSF) of patients with Parkinson's disease (PD) contains substance(s) that inhibit the growth and functions of dopaminergic neurons. Further, selegiline, a monoamine oxidase B (MAO) inhibitor (0.125-0.250 microM) enhanced the number of tyrosine hydroxylase (TH)-positive neurons, augmented the high affinity uptake of dopamine (DA), and averted the neurotoxic effects of CSF of PD patients on rat mesencephalic neurons in culture. The neuroprotective effects of selegiline may be related either to its ability to inhibit MAO B, preventing the generation of free radicals, or to neuronal rescue property due to unknown mechanisms.