Receptor for arginine vasopressin. The activity of this receptor is mediated by G proteins which activate a phosphatidyl-inositol-calcium second messenger system. Involved in social memory formation. Knockout mice display deficits in individual discrimination. Male mice lacking functional AVPR1A (V1aRKO) exhibit markedly reduced anxiety-like behavior and a profound impairment in social recognition. V1aRKO performed normally on spatial and non-social olfactory learning and memory tasks. Belongs to the G-protein coupled receptor 1 family. Vasopressin/oxytocin receptor subfamily.