Irritable Bowel Syndrome Message Boards

PMartin, this is all extremely complex.

However, its not the total amount of serotonin in the body, but the release of serotonin at the gut level from specific cells called EC cells or enterochromaffin cells.

So there is dysregulation of serotonin signaling first at the gut level. But also part of altered singaling to the brain, because its a major neurotramsitter that signals to the brain distress or pain in the digestive tract.

"In the gut, serotonin is synthesized by and stored in the enterochromaffin cells, which are located within the mucosa of the intestinal wall. When material passes through the lumen and the mucosa is stimulated, enterochromaffin cells release serotonin, which then binds to its receptors (primarily 5-HT1P receptors) on intrinsic primary afferent neurons, initiating peristalsis and secretion"

So these cells initiate peristalsis and secretion. Another words they intiate gut contractions.

So its not the total amount in the body per se, but the amount released from the ec cells and then what happens at the cellular level after its release.

So you know though high levels of serotonin in the brain can cause anxiety and the right amount in the brain can cause relaxation.

The serotonin in the gut does not go to the brain itself, but signals up nerve fibers to the brain, importantantly pain and discomfort.

I have a ton of information on all this so you know.

I have to post this as the link no longer exists.

June 19, 2001
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A:

Irritable bowel syndrome is now recognized as a disorder of serotonin activity. Serotonin is a neurotransmitter in the brain that regulates sleep, mood (depression, anxiety), aggression, appetite, temperature, sexual behavior and pain sensation. Serotonin also acts as a neurotransmitter in the gastrointestinal tract.

Excessive serotonin activity in the gastrointestinal system (enteric nervous system) is thought to cause the diarrhea of irritable-bowel syndrome. The enteric nervous system detects bowel distension (expansion) on the basis of pressure-sensitive cells in the bowel lumen (opening). Once activated, these pressure-sensitive cells promote the release of serotonin, which in turn promotes both secretory function and peristaltic function (the contractions of the intestines that force the contents outward). At least four serotonergic receptors have been identified to be participants in the secretory and peristaltic response.

Patients with diarrhea-predominant IBS may have higher levels of serotonin after eating than do people without the disorder. This recognition led to the development of the first drug used specifically to treat diarrheal symptoms of IBS, alosetron (also known as Lotronex). Alosetron blocked the specific serotonin receptors responsible for recognizing bowel distention. In doing so, it blocked the effects of serotonin and reduced both bowel secretions and peristalsis. Constipation was the most common side effect seen. (Note: Alosetron was removed from the market by the manufacturer after repeated reports of a dangerous condition known as ischemic colitis became known.) Tegaserod (Zelmac) is another drug under development and under review by the U.S. Food and Drug Administration for approval. Tegaserod is indicated for the treatment of constipation-predominant IBS and works to increase enteric nervous system serotonin activity.

So, increasing serotonin activity in the enteric nervous system produces increased bowel secretions and peristalsis (and potentially diarrhea), whereas depressing serotonin activity produces reduced secretions and reduce peristalsis (and potentially constipation). Increasing serotonin activity in the brain would increase awareness and, in higher doses, produce anxiety, insomnia and restlessness."

Taking 5htp is not likely to effect the bowel per se either, because that is not really how it works, tryptophan is the precursor to serotonin.

It might cause "anxiety, insomnia and restlessness" at the brain level, which could then contribute to more symptoms.

Or it may possible help calm a person, depending on how high it is in the brain to begin with so you know.

Over the years this question has been asked a lot and they don't really recommend taking 5htp supplements. You also have to e somewhat careful where the 5ht supplment comes from.

Video Corner: Serotonin

Increasingly our understanding of IBS is that it is a heterogeneous disorder � that is, multiple factors contribute to the well defined symptoms of the disorder. One of these suspected underlying dysfunctions involves serotonin, which is a neurotransmitter or messenger to nerves. Most serotonin in the body is in cells that line the gut where it senses what is going on and through receptors signals nerves that stimulate a response. The serotonin must then be reabsorbed (a process called re-uptake) into cells. This process appears to be disrupted in people with IBS.

Serotonin and SERT
How does serotonin affect gut function? An interview with Gary M. Mawe, PhD, Professor of Anatomy and Neurobiology, University of Vermont, Burlington, VT. Dr. Mawe is a basic scientist.

http://www.aboutibs.org/site/learning-center/video-corner/serotonin

Diet of course ccould possibly contribute to increase serotonin production at the gut level and this is being studied.

This is a part of what they have figured out, although not completely why there is altered motility in IBS, the d and c and d/c.

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My website on IBS is www.ibshealth.com

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