However, the intermediate tertiary alcohol is liable to dehydration in acidic conditions if the reaction temperature rises above -30°C, and, since Kidston did not realize this and esterified the intermediate with propionic anhydride at room temperature, MPTP was formed as a major impurity.[3] Several days after trying this new batch of his homemade drug, Kidston developed serious Parkinson's Disease symptoms, as did several friends he had shared the drug with.[4]
1-Methyl-4-phenylpyridinium (MPP+), a metabolite of MPTP, causes rapid onset of irreversible symptoms similar to Parkinson's Disease.[5][6] MPTP is metabolized to the neurotoxin MPP+ by the enzyme MAO-B, which is expressed in neurons. This selectively kills brain tissue in the area of the brain called the substantia nigra and causes Parkinsonian symptoms