Posted by zeugma on October 15, 2005, at 16:21:10
In reply to Re: are maoi's pro-histamine? » zeugma, posted by ed_uk on October 15, 2005, at 13:57:10
hi Ed,
thanks for the clarification.
so melatonin is an indoleamine? but MAOI's wouldn't necessarily boost melatonin, would they?
One of the more fascinating things I pulled up from PubMed's search engine is that caffeine actually boosts melatonin- through interactions with the 1A2 enzyme that also inactivates melatonin:
J Endocrinol Invest. 2003 May;26(5):403-6. Related Articles, Links
Caffeine raises the serum melatonin level in healthy subjects: an indication of melatonin metabolism by cytochrome P450(CYP)1A2.Ursing C, Wikner J, Brismar K, Rojdmark S.
Karolinska Institutet, Department of Internal Medicine, Endocrinology Section, Stockholm Soder Hospital, Stockholm, Sweden. carina.ursing@medklin.sos.sll.se
Caffeine is metabolized in the liver by cytochrome P450(CYP)1A2. Recent findings imply that this enzyme may also be of importance for the metabolism of human melatonin (MT). If caffeine and MT are metabolized by the same enzyme, one may expect to find different serum MT levels after ingestion of coffee compared with placebo. Although coffee is consumed by people all over the world, few studies have focused on whether caffeine actually affects serum MT levels in normal subjects. We decided to study that particular topic. For that purpose 12 healthy individuals were tested on two occasions, one week apart. On one of these occasions they were given a capsule containing 200 mg caffeine in the evening. On the other, they received placebo. The experimental order was randomized. Serum MT levels were determined every second hour between 22:00 h and 08:00 h, and the melatonin areas under the curve (MT-AUCs) were calculated. After caffeine the serum MT level rose from 0.09 +/- 0.03 nmol/l at 22:00 h to 0.48 +/- 0.07 nmol/l at 04:00 h. The corresponding rise after placebo was less prominent (from 0.06 +/- 0.01 to 0.35 +/- 0.06 nmol/l). This was reflected by the MT-AUC which was 32% larger after ingestion of caffeine compared with placebo (MT-AUC(caffeine) 3.16 +/- 0.44 nmol/l x h vs MT-AUC(placebo) 2.39 +/- 0.40 nmol/l x h; p < 0.02). These findings imply that caffeine, ingested in the evening at a dose corresponding to two ordinary cups of coffee, augments the nocturnal serum MT level, which in turn supports the notion that cytochrome P450(CYP)1A2 is involved in the hepatic metabolism of human MT.
Maybe this is in part responsible for caffeine's antidepressant effect. Incidentally Provigil induces 1A2 so it probably lowers melatonin levels. Fluvoxamine probably raises melatonin, unless it has another mechanism that counteracts this.
This is one of those days where I wish I knew where I was talking about.
-z
poster:zeugma
thread:566726
URL: http://www.dr-bob.org/babble/20051010/msgs/567238.html