The Transmethylation Hypothesis Restated
I want to briefly discuss the transmethylation hypothesis and try to restate it in a way that will incorporate some more recent findings. There appears to be considerably greater support for this hypothesis from recent biochemical and pharmacological findings than from therapeutic tests involving the administration of nicotinic acid and nicotinamide. When Harley-Mason, Smythies, and Osmond proposed the transmethylation hypothesis, they were concerned principally with the possibility that epinephrine might be methylated to an analog of mescaline or to a hallucinogenic molecule. More recently a number of investigations have been concerned with the role of dopamine, rather than epinephrine, in psychosis, and the possible involvement of methylated derivatives of dopamine. This change in interest has occurred largely because of the discovery that a decrement in dopaminergic activity is responsible for the pathology in both drug-induced and naturally occurring Parkinsonism.
KeywordsNicotinic Acid Antipsychotic Drug Mammalian Tissue Enzymatic Formation Dopaminergic Activity
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