Clinic Notes: Dopamine 101

Tourette’s is caused by an excess of the neural transmitter, dopamine. Parkinson’s disease is caused by a depletion of dopamine producing neurons in an area of the brain called the substantia nigra. Dopamine agonist such as L-dopa can temporally alleviate the paralyzing effects of Parkinson’s just as dopamine antagonists, like haloperidol, temporally relieve the Touretter of his tics.
In the 1980s, synthetic heroin contaminated with MPTP appeared on the streets. Several addicts who injected this contaminated heroin became “frozen” and were admitted to psychiatric hospitals with a diagnosis of catatonic schizophrenia.
On closer examination, animal studies indicated that MPTP metabolized to a neurotoxin that destroyed dopamine neurons in the substantia nigra just like Parkinson’s. These frozen addicts were nearly mute, and somewhat like patients with locked-in syndrome.
See Case History # 9 in Little Bubba's Not Ready for Nashville Yet at http://www.aba4autism.com