mptp

MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) is a neurotoxin that causes permanent symptoms of Parkinson's disease by killing certain neurons in the substantia nigra of the brain. It is used to study the disease in monkeys.

While MPTP itself does not have opioid effects, it is related to MPPP, a synthetic opioid drug with effects similar to those of heroin and morphine. MPTP can be accidentally produced during the illicit manufacture of MPPP, and that is how its Parkinson-inducing effects were first discovered.

Nicholas S.S Athwal has written:

'Interactions of MPTP and analogues with dopamine-containing cells'

There are some known toxins that can cause parkinsonism, most notoriously a chemical called MPTP, found as an impurity in some illegal drugs

There seems to be no direct link between heroin use and Parkinson's disease (please correct me if I'm wrong). There is a link however between the synthetic heroin analog MPPP and Parkinson's disease. In the synthesis of this (illegal) drug, traces of the neurotoxin MPTP are sometimes formed, which destroys the same cells in the brain (the substantia nigra) that are affected in Parkinon's disease. For more information, please see http://en.wikipedia.org/wiki/MPTP