Serotonin 1A receptor; Serotonin 1B receptor (5-HT1A; 5-HT1B)

The serotonin 1A and 1B receptors (5-HT1A and 5-HT1B) are subtypes of the serotonin (5-hydroxytryptamine, 5-HT) receptor family, belonging to the class A G protein-coupled receptors. 5-HT1A is widely distributed in the central nervous system, notably in the cerebral cortex, hippocampus, septum, amygdala, and raphe nuclei, where it functions both as an autoreceptor on serotonergic neurons and as a postsynaptic receptor. 5-HT1B is expressed primarily in presynaptic neurons in the CNS and in peripheral vasculature and acts mainly as a terminal autoreceptor. Both receptors are primarily coupled to Gi/Go proteins, leading to inhibition of adenylyl cyclase and decreased cyclic AMP levels, which dampens neuronal excitability and neurotransmitter release[1][2][4][5][7]. 5-HT1A plays critical roles in mood regulation, cognition, anxiety, sleep, and stress response, and is a key therapeutic target in depression and anxiety disorders[1][5][7]. 5-HT1B regulates serotonin release and vascular tone and is crucial in migraine pathophysiology, making it a primary target of antimigraine "triptan" drugs[1][3][7]. Drugs modulating these receptors include agonists, partial agonists, antagonists, and inverse agonists, with clinical applications in psychiatry and neurology. Safety concerns include cardiovascular risks (mainly 5-HT1B agents) and neuropsychiatric side effects.

Other names

5-HT1A receptor5-HT1B receptor5-hydroxytryptamine receptor 1A5-hydroxytryptamine receptor 1BHTR1A (gene for 5-HT1A)HTR1B (gene for 5-HT1B)

Agonists activate Gi/Go-coupled signaling to decrease cAMP production, leading to neuronal inhibition or decreased neurotransmitter release[1][3][6][7]. Antagonists or inverse agonists block or reduce receptor activity, increasing serotonergic neurotransmission or causing other effects[3]. 5-HT1A partial agonists (e.g., buspirone) function as anxiolytics/antidepressants; full or partial 5-HT1B agonists (e.g., triptans) cause vasoconstriction, effective in migraine[1][3][7].