5-hydroxytryptamine receptor 1A (HTR1A) (HTR1A)

The 5-hydroxytryptamine receptor 1A (HTR1A) is a prominent G protein-coupled receptor (GPCR) that mediates the inhibitory effects of serotonin in the central nervous system (UniProt P08908). It is expressed as a presynaptic autoreceptor in the raphe nuclei, where it regulates serotonin release, and as a postsynaptic heteroreceptor in regions like the hippocampus and cortex, influencing mood and cognition (PubMed: 29034404). HTR1A plays a critical role in modulating neurotransmission, and its dysregulation is linked to major depressive disorder, anxiety, and schizophrenia (NIH: StatPearls). Drugs like aripiprazole act as high-affinity partial agonists at this receptor, which helps stabilize serotonergic activity and contributes to their antipsychotic and antidepressant efficacy (PubChem CID 60795). This partial agonism is thought to provide a tuning effect, enhancing serotonin signaling where it is low and dampening it where it is excessive. Beyond psychiatric conditions, HTR1A is a target for managing neurodegenerative symptoms and is studied for its role in neuroprotection and thermoregulation. The receptor's involvement in the hypothalamic-pituitary-adrenal (HPA) axis also makes it a key player in the biological response to stress. Clinical research continues to evaluate HTR1A as a biomarker for treatment resistance in depression and as a target for novel rapid-acting antidepressants.

Other names

Serotonin receptor 1A5-HT1AADRBRL1ADRB2L1G-21

Partial agonism, full agonism, or antagonism of the G protein-coupled signaling pathway, typically involving inhibition of adenylyl cyclase and activation of G protein-coupled inwardly-rectifying potassium (GIRK) channels.