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Rationale for deprenyl (selegiline)
medication in Parkinson's disease and in prevention of age-related nigral
changes.
Knoll J.
Department of Pharmacology,
Semmelweis University of Medicine, Budapest, Hungary.
Biomed Pharmacother 1995;49(4):187-95
Abstract
Deprenyl (selegiline, jumex, eldepryl,
movergan), a close structural relative to phenylethylamine (PEA), is a drug
with a unique pharmacological spectrum. It is a highly potent and selective,
irreversible inhibitor of B-type monoamine oxidase (MAO), a predominantly
glial enzyme in the brain. The activity of this enzyme significantly
increases with age. (-)deprenyl, the first selective inhibitor of MAO-B
described in literature, has become the universally used research tool for
selectively blocking B-type MAO. It is the only selective MAO-B inhibitor in
clinical use. (-)Deprenyl interferes with the uptake of catecholamines and
indirectly acting sympathomimetics because it is handled by the
catecholaminergic neuron in a way similar to the physiological substances
transported through the axonal end organ and vesicular membrane. The unique
behavior of (-)deprenyl is that, in striking contrast to PEA and its
relatives it does not displace the transmitter from storage, ie it is not a
releaser. The net result is that (-)deprenyl inhibits the releasing effect
of tyramine, and at present, is the only safe MAO inhibitor that can be
administered without dietary precautions. Maintenance on (-)deprenyl
selectively enhances superoxide dismutase (SOD) and catalase activity in the
striatum. This effect is unrelated to its effect on MAO-B and the inhibitory
effects of the drug on neurotransmitter uptake. Maintenance on (-)deprenyl
facilitates the activity of the catecholaminergic system in the brain, and
this effect, too, is unrelated to either its effects on MAO or on
neurotransmitter uptake. (-)Deprenyl protects the nigrostriatal dopaminergic
neurons against selective neurotoxins (6-hydroxydopamine, MPTP, DSP-4).
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