K. Taniyama et al., Functions of peripheral 5-hydroxytryptamine receptors, especially 5-hydroxytryptamine(4) receptor, in gastrointestinal motility, J GASTRO, 35(8), 2000, pp. 575-582
The multiple 5-hydroxytryptamine (5-HT, serotonin) receptor subtypes are di
stinguished. In this article, we described mainly the 5-HT4 receptor of fou
r subtypes of functional 5-HT receptors, 5-HT1, 5-HT2, 5-HT3, and 5-HT4, re
cognized in the gastrointestinal tract. In-vivo microdialysis experiments d
etermined that activation of the 5-HT4 receptor stimulated intestinal motor
activity associated with a local increase in acetylcholine (ACh) release f
rom the intestinal cholinergic neurons in the whole body of dogs. The 5-HT4
receptor-mediated response of ACh release in the antral, corporal, and fun
dic strips isolated from guinea pig stomach corresponds to the presence of
5-HT4 receptor in the myenteric plexus. In-vitro receptor autoradiograms of
the stomach and colon indicate that the distribution of 5-HT4 receptors in
human tissues is similar to that in the guinea pig, although density of 5-
HT4 receptors in the myenteric plexus of human tissues is lower than that i
n guinea pig tissues. The 5-HT4 receptors located in the myenteric plexus m
ay participate in gastrointestinal motility, and thus the 5-HT4 agonists an
d antagonists may be available for treatment of dysfunction of gastrointest
inal motility.