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. In prairie and pine voles, the 5' regulatory region of AVPR1A contains a microsatellite region that is virtually absent from montane and meadow voles. This species-specific microsatellite polymorphism modulates gene expression in a cell-type-dependent manner and generates a great individual variability in the brain expression pattern. This polymorphism is correlated with monogamous social organization. Prairie voles exhibit a monogamous social structure in nature, whereas closely related meadow voles are solitary and polygamous. AVPR1A is expressed at higher levels in the ventral forebrain of monogamous than in promiscuous vole species, whereas dopamine receptor distribution is relatively conserved between species. The partner preference formation in the socially promiscuous meadow vole is increased by AVPR1A gene transfer into the ventral forebrain. Belongs to the G-protein coupled receptor 1 family. Vasopressin/oxytocin receptor subfamily. Nature's philanderers - Issue 52 of November 2004