Permanent human parkinsonism due to 1‐methy 1–4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP)

Seven patients developed chronic and severe parkinsonism after repeatedly injecting 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intravenously. Levodopa and bromocriptine controlled the symptoms; however, within months, five of the seven patients experienced dyskinesias or on-off fluctuations. Therefore, neither prolonged levodopa treatment nor progressive disease was necessary for on-off phenomena. Because the neurotoxic effects of MPTP seem limited to the substantia nigra, damage to this system alone may produce all the motor features of Parkinson's disease. MPTP differs from other neurotoxins in that it consistently produces a pure parkinsonian state.