Previous studies showed that 5 μg of ramosetron, a serotonin (5-hydroxytryptamine: 5-HT)-3 receptor antagonist, is only effective in male patients with irritable bowel syndrome (IBS) with diarrhea (IBS-D).
The second objective is to review pharmacogenetics in IBS, with the focus on cytochrome P-450 metabolism of drugs used in IBS, modulation of motor and sensory responses to serotonergic agents based on the 5-hydroxytryptamine (5-HT) transporter-linked polymorphic region (5-HTTLPR) and 5-HT(3) genetic variants, responses to a nonselective cannabinoid agonist (dronabinol) based on cannabinoid receptor (CNR1) and fatty acid amide hydrolase (FAAH) variation, and responses to a bile acid (sodium chenodeoxycholate) and bile acid binding (colesevelam) based on klothoβ (KLB) and fibroblast growth factor receptor 4 (FGFR4) variation.
Owing to their expression profile and physiological functions, 5-HT(3) receptors have been implicated in irritable bowel syndrome (IBS) and psychiatric disorders.
First evidence for an association of a functional variant in the microRNA-510 target site of the serotonin receptor-type 3E gene with diarrhea predominant irritable bowel syndrome.