However, the amount of melatonin produced in the GI tract by enterochromaffin
cells is 400 times greater than that produced by the pineal gland.
MIBG imaging is reserved for situations where the tumours are thought to be of enterochromaffin
Serotonin (5'-hydroxy tryptamine; 5-HT) is a bioamine, which is synthesized from L-tryptophan mainly in enterochromaffin
cells of the gastrointestinal tract and central nervous system.
Some tumors contain small intestinal-type cells, such as Paneth cells and enterochromaffin
Serotonin released from the enterochromaffin
cells (ECC) during postprandial parasympathetic drives19,20 modulates both beta and alpha cells.
It is secreted by the enterochromaffin
cells of the microvilli and it promotes peristalsis in the GIT.
Chemotherapeutic agents release serotonin from the enterochromaffin
cells of the small intestine; this released serotonin is free to activate 5-H[T.
Important depots in mammals were enterochromaffin
cells in the gastrointestinal mucosa, serotonergic neurones of the brain, the pineal gland, and platelets.
Produced in the GI tract's enterochromaffin
cells, serotonin levels have been found to be low in some studies of FM and MD.
We selected carcinoid tumors by specifying carcinoid NOS (8240), somato statinoma (8156), enterochromaffin
cell (8241), goblet cell (8243), and composite (8244)-type carcinoids.
The above hyperparasympathetic activity is explained because plasma serotonin excites the medullary area postrema located outside the blood brain barrier and activates parasympathetic mechanisms that increase the release of serotonin from the enterochromaffin
cells, associated with the blood pressure and heart rate decreases.
The neurotransmitter/neurohormone serotonin [5-hydroxytryptamine (5-HT)]  is synthesized from the essential amino acid tryptophan in the enterochromaffin
cells of the gut and in serotonergic neurons in the central nervous system (1, 2).