Perhaps you might consider daring to self experiment with melatonin?

Nun Giver

2012-12-22 07:02:57 UTC

Full text is free:

1. J Physiol Pharmacol. 2011 Apr;62(2):139-50.

Gut clock: implication of circadian rhythms in the gastrointestinal tract.

Konturek PC, Brzozowski T, Konturek SJ.

Department of Medicine, Thuringia-Clinic Saalfeld, Teaching Hospital of the
University of Jena, Germany. ***@thueringen-kliniken.de

Circadian and seasonal rhythms are a fundamental feature of all living organisms
and their organelles. Biological rhythms are responsible for daily food intake;
the period of hunger and satiety is controlled by the central pacemaker, which
resides in the suprachiasmatic nucleus (SCN) of the hypothalamus, and
communicates with tissues via bidirectional neuronal and humoral pathways. The
molecular basis for circadian timing in the gastrointestinal tract (GIT) involves
interlocking transcriptional/translational feedback loops which culminate in the
rhythmic expression and activity of a set of clock genes and related hormones.
Interestingly, it has been found that clocks in the GIT are responsible for the
periodic activity (PA) of its various segments and transit along the GIT; they
are localized in special interstitial cells, with unstable membrane potentials
located between the longitudinal and circular muscle layers. The rhythm of slow
waves is controlled in various segments of the GIT: in the stomach (about 3
cycles per min), in the duodenum (12 cycle per min), in the jejunum and ileum
(from 7 to 10 cycles per min), and in the colon (12 cycles per min). The
migrating motor complex (MMC) starts in the stomach and moves along the gut
causing peristaltic contractions when the electrical activity spikes are
superimposed on the slow waves. GIT hormones, such as motilin and ghrelin, are
involved in the generation of MMCs, while others (gastrin, ghrelin,
cholecystokinin, serotonin) are involved in the generation of spikes upon the
slow waves, resulting in peristaltic or segmental contractions in the small
(duodenum, jejunum ileum) and large bowel (colon). Additionally, melatonin,
produced by neuro-endocrine cells of the GIT mucosa, plays an important role in
the internal biological clock, related to food intake (hunger and satiety) and
the myoelectric rhythm (produced primarily by the pineal gland during the dark
period of the light-dark cycle). This appears to be an endocrine encoding of the
environmental light-dark cycle, conveying photic information which is used by
organisms for both circadian and seasonal organization. Motor and secretory
activity, as well as the rhythm of cell proliferation in the GIT and liver, are
subject to many circadian rhythms, mediated by autonomic cells and some
enterohormones (gastrin, ghrelin and somatostatin). Disruption of circadian
physiology, due to sleep disturbance or shift work, may result in various
gastrointestinal diseases, such as irritable bowel syndrome (IBS),
gastroesophageal reflux disease (GERD) or peptic ulcer disease. In addition,
circadian disruption accelerates aging, and promotes tumorigenesis in the liver
and GIT. Identification of the molecular basis and role of melatonin in the
regulation of circadian rhythm allows researchers and clinicians to approach
gastrointestinal diseases from a chronobiological perspective. Clinical studies
have demonstrated that the administration of melatonin improves symptoms in
patients with IBS and GERD. Moreover, our own studies indicate that melatonin
significantly protects gastrointestinal mucosa, and has strong protective effects
on the liver in patients with non-alcoholic steatohepatitis (NASH). Recently, it
has been postulated that disruption of circadian regulation may lead to obesity
by shifting food intake schedules. Future research should focus on the role of
clock genes in the pathophysiology of the GIT and liver.

PMID: 21673361 [PubMed - indexed for MEDLINE]