|
In the field of neurochemistry, 5-HT receptors are receptors for the neurotransmitter and peripheral signal mediator serotonin, also known as 5-hydroxytryptamine or 5-HT. 5-HT receptors are located on the cell membrane of nerve cells and other cell types in animals and mediate the effects of serotonin as the endogenous ligand and of a broad range of pharmaceutical and recreational drugs. With the exception of the 5-HT3 receptor, a ligand gated ion channel, all other 5-HT receptors are G_protein coupled seven transmembrane (or heptahelical) receptors that activate an intracellular second messenger cascade.
- 5-HT2 receptors are Gq/G11 coupled, mediating cellular effects through increasing cellular levels of inositol trisphosphate (IP3) and diacylglycerol (DAG). Three subtypes exist, namely 5-HT2A, 5-HT2B, and 5-HT2C (formerly called 5-HT1C).
- The 5-HT4 receptor is Gs coupled, mediating cellular effects through increasing cellular levels of cAMP.
- The 5-HT7 receptors is Gs coupled, mediating cellular effects through increasing cellular levels of cAMP.
Characterised 5-HT receptors
Within these general classes of 5-HT receptors, a number of specific types have been characterized:
| Summary of characterised 5-HT receptors, with selected agonist/antagonist agents
|
| receptor
| actions
| agonists
| antagonists
|
| 5-HT1A
| CNS: neuronal inhibition, behavioural effects (sleep, feeding, thermoregulation, anxiety)
| buspirone
| spiperone, methiothepin, ergotamine, yohimbine
|
| 5-HT1B
| CNS: presynaptic inhibition, behavioural effects; vascular: pulmonary vasoconstriction
| ergotamine, sumatriptan
| methiothepin, yohimbine, metergoline
|
| 5-HT1D
| CNS: locomotion; vascular: cerebral vasoconstriction
| sumatriptan
| methiothepin, yohimbine, metergoline, ergotamine
|
| 5-HT2A
| CNS: neuronal excitation, behavioural effects; smooth muscle: contraction, vasoconstriction/dilatation; platelets: aggregation
| α-methyl-5-HT, LSD (CNS)
| ketanserin, cyproheptadine, pizotifen, LSD (PNS)
|
| 5-HT2B
| stomach: contraction
| α-methyl-5-HT, LSD (CNS)
| yohimbine, LSD (PNS)
|
| 5-HT2C
| CNS, choroid plexus: cerebrospinal fluid (CSF) secretion
| α-methyl-5-HT, LSD (CNS)
| mesulergine, LSD (PNS)
|
| 5-HT3
| CNS, PNS: neuronal excitation, anxiety, emesis
| 2-methyl-5-HT
| metoclopramide (high doses), renzapride, ondansetron, alosetron
|
| 5-HT4
| GIT, CNS: neuronal excitation, gastrointestinal motility
| 5-methoxytryptamine, metoclopramide, renzapride, tegaserod
| GR113808
|
| 5-ht5
| CNS: unknown
| unknown
| unknown
|
| 5-ht6
| CNS: unknown
| unknown
| unknown
|
| 5-HT7
| CNS, GIT, blood vessels: unknown
| 5-carboxytryptamine, LSD
| methiothepin
|
Note that there is no 5-HT1C receptor since, after the receptor was cloned and further characterised, it was found to have more in common with the 5-HT2 family of receptors and was redesignated as the 5-HT2C receptor.
External links
|
