Human AVPR1A cDNA is 1472 bp long and encodes a 418 amino-acid long polypeptide which shares 72%, 36%, 37%, and 45% sequence identity with rat Avpr1a, human AVPR2, rat Avpr2, and human oxytocin receptor (OXTR), respectively. AVPR1A is a G-protein coupled receptor (GPCR) with 7 transmembrane domains that couples to Gaq/11 GTP binding proteins, which along with Gbl, activate phospholipase C activity.[5][6] Clinically, the V1A receptor is related to vasoconstriction compared to the V1B receptor that is more related to ACTH release or the V2 receptor that is linked to the diuretic function of ADH.