Differential trace amine alterations in individuals receiving acetylenic inhibitors of MAO-A (clorgyline) or MAO-B (selegiline and pargyline)

J Neural Transm Suppl. 1998;52:39-48. doi: 10.1007/978-3-7091-6499-0_5.


Marked, dose-dependent elevations in the urinary excretion of phenylethylamine, para-tyramine, and meta-tyramine were observed in depressed patients treated for three or more weeks with 10, 30, or 60 mg/day of the partially-selective inhibitor of MAO-B, selegiline (l-deprenyl). In comparative studies with other, structurally similar acetylenic inhibitors of MAO, pargyline, an MAO-B > MAO-A inhibitor used in doses of 90 mg/day for three or more weeks, produced elevations in these trace amines which were similar to those found with the highest dose of selegiline studied. Clorgyline, a selective inhibitor of MAO-A used in doses of 30 mg/day for three or more weeks (a dose/time regimen previously reported to reduce urinary, plasma, and cerebrospinal fluid 3-methoxy-4-hydroxyphenylethyleneglycol (MHPG) > 80%, indicating a marked inhibitory effect on MAO-A in humans in vivo) produced negligible changes in trace amine excretion. In comparison to recent studies of individuals lacking the genes for MAO-A, MAO-B, or both MAO-A and MAO-B, the lack of change in trace amine excretion in individuals with a mutation affecting only MAO-A is in agreement with the observed lack of effect of clorgyline in the present study. Selegiline produced larger changes in trace amines--at least at the higher doses studied--than found in individuals lacking the gene for MAO-B, in agreement with other data suggesting a lesser selectivity for MAO-B inhibition when selegiline was given in doses higher than 10 mg/day. Overall, trace amine elevations in individuals receiving the highest dose of deprenyl or receiving pargyline were approximately three to five-fold lower than the elevations observed in individuals lacking the genes for both MAO-A and MAO-B, suggesting that these drug doses yield incomplete inhibition of MAO-A and MAO-B.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial

MeSH terms

  • Biogenic Amines / urine*
  • Chromosome Deletion
  • Clorgyline / therapeutic use*
  • Depressive Disorder / drug therapy*
  • Depressive Disorder / urine*
  • Humans
  • Isoenzymes / antagonists & inhibitors
  • Isoenzymes / deficiency
  • Isoenzymes / genetics
  • Male
  • Monoamine Oxidase / deficiency
  • Monoamine Oxidase / genetics
  • Monoamine Oxidase Inhibitors / therapeutic use*
  • Pargyline / therapeutic use*
  • Phenethylamines / urine
  • Reference Values
  • Retrospective Studies
  • Selegiline / therapeutic use*
  • Tyramine / urine
  • X Chromosome


  • Biogenic Amines
  • Isoenzymes
  • Monoamine Oxidase Inhibitors
  • Phenethylamines
  • Selegiline
  • Pargyline
  • Monoamine Oxidase
  • 3-tyramine
  • Clorgyline
  • Tyramine