Table 1.
Serotonin receptor characteristics.
| Receptor Type | Signal Transduction Pathway | Subtype | Location | Response |
|---|---|---|---|---|
| 5-HT1 | G1/G0-Adenylyl cyclase | 1A | Mainly CNS | Neuronal hyperpolarization |
| G1/G0-Adenylyl cyclase | 1B | CNS and peripheral nerves | Inhibits neurotransmitter release | |
| G1/G0-Adenylyl cyclase | 1D | Mainly CNS | Inhibits neurotransmitter release | |
| G1/G0-Adenylyl cyclase | 1E | CNS | Inhibits adenylyl cyclase | |
| G1/G0-Adenylyl cyclase | 1F | Mainly CNS | Inhibits adenylyl cyclase | |
| 5-HT2 | Gq/G11-Phospholipase C | 2A | Vascular smooth muscles, platelets, lung, CNS, GI tract | Vasoconstriction, platelet aggregation, broncho-constriction |
| Gq/G11-Phospholipase C | 2B | Mainly peripheral | Rat stomach muscle contraction | |
| Gq/G11-Phospholipase C | 2C | CNS (concentrated in choroid plexus) | Increases turnover of phosphoinositide | |
| 5-HT3 | Ligand-gated cation channel | - | Peripheral and central neurons | Depolarization |
| 5-HT4 | Gs-Adenylyl cyclase | - | GI tract, CNS, heart, urinary bladder | Acetylcholine release in gut, tachycardia, release cAMP in CNS neurons |
| 5-HT5 | G1/G0- Adenylyl cyclase | 5A | CNS | Unknown |
| 5B | Absent in human | |||
| 5-HT6 | Gs -Adenylyl cyclase | - | CNS | Activates adenylyl cyclase |
| 5-HT7 | Gs -Adenylyl cyclase | - | CNS | Activates adenylyl cyclase |