The function of Ensembl gene identifier ENSG00000102468 (HTR2A, 5-hydroxytryptamine receptor 2A) is as follows. G protein-coupled receptor for 5-hydroxytryptamine (serotonin) (PubMed:1330647, PubMed:18703043, PubMed:19057895, PubMed:21645528, PubMed:22300836, PubMed:35084960, PubMed:38552625). Also functions as a receptor for various drugs and psychoactive substances, including mescaline, psilocybin, 1-(2,5-dimethoxy-4- iodophenyl)-2-aminopropane (DOI) and lysergic acid diethylamide (LSD) (PubMed:28129538, PubMed:35084960). Ligand binding causes a conformation change that triggers signaling via guanine nucleotide- binding proteins (G proteins) and modulates the activity of downstream effectors (PubMed:28129538, PubMed:35084960). HTR2A is coupled to G(q)/G(11) G alpha proteins and activates phospholipase C-beta, releasing diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3) second messengers that modulate the activity of phosphatidylinositol 3- kinase and promote the release of Ca(2+) ions from intracellular stores, respectively (PubMed:18703043, PubMed:28129538, PubMed:35084960). Beta-arrestin family members inhibit signaling via G proteins and mediate activation of alternative signaling pathways (PubMed:28129538, PubMed:35084960). Affects neural activity, perception, cognition and mood (PubMed:18297054). Plays a role in the regulation of behavior, including responses to anxiogenic situations and psychoactive substances. Plays a role in intestinal smooth muscle contraction, and may play a role in arterial vasoconstriction (By similarity). {ECO:0000250|UniProtKB:P35363, ECO:0000269|PubMed:1330647, ECO:0000269|PubMed:18297054, ECO:0000269|PubMed:18703043, ECO:0000269|PubMed:19057895, ECO:0000269|PubMed:21645528, ECO:0000269|PubMed:22300836, ECO:0000269|PubMed:28129538, ECO:0000269|PubMed:35084960, ECO:0000269|PubMed:38552625}. (Microbial infection) Acts as a receptor for human JC polyomavirus/JCPyV. .