Table 2.
Localization and function of protease-activated receptors in the GI tract
| Localization in the GI tract | Known functions | |
|---|---|---|
| PAR1 | Enterocytes | Increase permeability, apoptosis, chloride secretion, prostaglandin release |
| Human colon cancer epithelium | Proliferation and motility | |
| Myenteric neurons | Suppression of fast excitatory postsynaptic potential | |
| Submucosal neurons | Inhibition of chloride secretion, | |
| Fibroblasts | Prostaglandin release | |
| Mast cells | ||
| Smooth muscle | Relaxation/contraction | |
| Endothelium | Gap formation | |
| PAR2 | Enterocytes | Chloride secretion, prostaglandin production, eicosanoid production |
| Human colon cancer epithelium | Proliferation | |
| Myenteric neurons | Neuropeptide release, increased excitability, suppression of fast excitatory postsynaptic potential | |
| Submucosal neurons | Neuropeptide release, stimulate epithelial ion secretion, hyperexcitability | |
| Fibroblasts | Prostaglandin release, proliferation | |
| Mast cells | ||
| Smooth muscle | Relaxation/contraction | |
| Pancreatic duct epithelium | Ion channel activation | |
| Pancreatic acinar cells | Amylase secretion | |
| Endothelium/leukocyte interface | Rolling, adhesion, transmigration, gap formation | |
| PAR3 | Detected by RT–PCR in whole GI tissues (stomach and small intestine), but unidentified cell type | |
| PAR4 | Enterocytes | |
| Submucosa | Contraction of longitudinal muscle | |
| Enteric neurons | Depolarization | |
| Endothelium/leukocyte interface | Rolling, adhesion, transmigration |