Tyramine pressor sensitivity changes during deprenyl treatment

Deprenyl has previously been reported to be a selective monoamine oxidase (MAO) type B inhibitor, which is associated with little or no enhancement of the pressor effects of tyramine. Employing an intravenous steady-state tyramine infusion technique, the effects of different doses of deprenyl and, f...

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Bibliographic Details
Published in:Psychopharmacologia 1985-01, Vol.86 (4), p.432-437
Main Authors: SUNDERLAND, T, MUELLER, E. A, COHEN, R. M, JIMERSON, D. C, PICKAR, D, MURPHY, D. L
Format: Article
Language:English
Subjects:
Biological and medical sciences
Blood Pressure - drug effects
Dose-Response Relationship, Drug
Humans
Medical sciences
Methoxyhydroxyphenylglycol - blood
Monoamine Oxidase - blood
Neuropharmacology
Pharmacology. Drug treatments
Phenethylamines - pharmacology
Psychoanaleptics: cns stimulant, antidepressant agent, nootropic agent, mood stabilizer..., (alzheimer disease)
Psychology. Psychoanalysis. Psychiatry
Psychopharmacology
Selegiline - pharmacology
Tyramine - pharmacology
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Summary:Deprenyl has previously been reported to be a selective monoamine oxidase (MAO) type B inhibitor, which is associated with little or no enhancement of the pressor effects of tyramine. Employing an intravenous steady-state tyramine infusion technique, the effects of different doses of deprenyl and, for comparison, the mixed inhibitor tranylcypromine on the pressor response to tyramine were studied in 11 depressed patients. After 3 weeks of treatment, deprenyl produced dose-proportionate increases in tyramine sensitivity at all three doses (10, 30, and 60 mg/day) when compared to placebo baseline tyramine responses. While only a modest (3.7-fold) increase in tyramine sensitivity was found with the 10 mg/day deprenyl dose, the increase in tyramine sensitivity at the 60 mg/day dose of deprenyl (22-fold) approached that found with tranylcypromine. Reductions in plasma 3-methoxy,4-hydroxyphenylglycol (MHPG), used as a possible index of in vivo MAO-A inhibition, were highly correlated with increases in tyramine pressor sensitivity (r = 0.82). The data suggest that deprenyl acts as a relatively selective MAO-B inhibitor at low doses, but that this selectivity is lost at higher doses, resulting in a significant "crossover" inhibition of MAO-A and increased tyramine pressor sensitivity.
ISSN:0033-3158
1432-2072
DOI:10.1007/BF00427904