Does moclobemide stimulate melatonin synthesis as the other selective MAO-A inhibitors do?
It has been reported that selective MAO-A inhibitors, clorgyline and brofaromine, but not the MAO-B inhibitors, deprenyl and pargyline, stimulated rat pineal melatonin synthesis in humans and animals. Recent studies, however, found no effect of moclobemide, a selective MAO-A inhibitor, on human plasma melatonin levels. Present study found that in vitro moclobemide produced very weak stimulation of rat pineal NAT activity. However, in vivo moclobemide induced a significant increase of rat pineal NAS and melatonin content, and a dramatic decrease of 5-HIAA content (HPLC-fluorimetric procedure). Moclobemide's effect on melatonin and related indoles could be detected as early as 30 min after the injection and lasted, at least, for 2 h. The possible reasons for discrepancies between human and animal data are discussed.
Oxenkrug
G F
GF
Brown University, VAMC, Providence, Rhode Island.
Requintina
P J
PJ
Yuwiler
A
A
D000123:Acetyltransferases / Q000378:metabolism; D000818:Animals; D001549:Benzamides / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008550:Melatonin / Q000096:biosynthesis*; D020912:Moclobemide; D008995:Monoamine Oxidase / Q000378:metabolism; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology*; D010870:Pineal Gland / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D013050:Spectrometry, Fluorescence
D001549:Benzamides; D008996:Monoamine Oxidase Inhibitors; D008995:Monoamine Oxidase; D000123:Acetyltransferases; D008550:Melatonin; D020912:Moclobemide