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 eflect 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.
KeywordsMelatonin Synthesis Pineal Melatonin BioI Psychiatry Weak Stimulation Melatonin Content
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- Bieck PR, Muhlbauer B, Antonin KH (1989) Differential effects of brofaromine and moclobemide on melatonin secretion. In: Stefanis CN, Soldatos CR, Rabavilas AD (eds) Psychiatry today. Abstracts of the 7th World Congress of Psychiatry, Athens, 1989. Excerpta Medica, International Congress Series 899, p 503, abstract 1946.Google Scholar
- Oxenkrug G, McCauley R, McIntyre I, Filipowicz C (1984) Effect of clorgyline and deprenyl on rat pineal melatonin. J Pharm Pharmacol 36:55W.Google Scholar
- Oxenkrug GF (1990) The acute effect of monoamine oxidase inhibitors on serotonin conversion to melatonin. In: Sandier M, Coppen A, Harnett S (eds) 5-Hydroxytryptamine in psychiatry: spectrum of ideas. Oxford University Press, pp 98-109.Google Scholar