5 HT receptors in CNS are all G-protein coupled receptors except 5HT3 receptors (ligand gated cation channel).
14 identified sub types.
5HT1 : mainly inhibitory, 5HT1A : autoreceptors that limit rate of firing of cells, widely distributed in limbic system and main target to treat anxiety and depression (5HT1A antagonist, Buspirone used for anxiety).
5HT1B & 5HT1D receptors : in basal ganglia
5HT1D agonists (Sumatriptan): used to treat migraine.
5HT2 (mainly 5HT2A) : excitatory postsynaptic effect and abundant in cortex and limbic system, target of hallucinogenic drugs, 5HT2 antagonists (methysergic) are used for treatment of migraine.
5HT3 : area postrema (in medulla, involved in vomiting) and other parts of brainstem extending to dorsal horn of spinal cord, cortex and PNS. 5HT3 antagonists (Ondansetron) are used to treat nausea and vomiting.
5HT4 : important in GIT, also present in CNS especially in striatum enhancing cognitive performance.
5HT6 : occur only in CNS, in hippocampus, cortex and limbic system, potential target for treatment of cognition and schizophrenia.
5HT7: hippocampus, cortex, thalamus and hypothalamus, blood vessels and GIT. May have thermoregulatory and endocrine function, cognitive function and sleep.
2 years ago