AT1 Receptor

AT1 receptor (angiotensin II type 1 receptor, AGTR1) is a major effector of the renin-angiotensin system and mediates the classical biological actions of angiotensin II, including vasoconstriction, aldosterone regulation, renal sodium handling, and cardiovascular remodeling^[1][2]. Mechanistically, AT1 receptor activation couples predominantly to heterotrimeric G proteins and stimulates phospholipase C, intracellular Ca²⁺ mobilization, protein kinase C activation, and downstream tyrosine kinase signaling pathways that regulate cellular growth, inflammation, and extracellular matrix formation^[1][3]. In cardiovascular and renal disease models, enhanced AT1 signaling promotes vascular smooth muscle cell proliferation, cardiac hypertrophy, fibrosis, and maladaptive tissue remodeling, supporting its central role in hypertension, heart failure, and chronic kidney injury research^[2][4]. Compared with the related AT2 receptor, which often mediates distinct or counter-regulatory functions, AT1 receptor is the dominant subtype responsible for the major physiological and pathological responses to angiotensin II in adult tissues^[5][6]. Rodent studies further demonstrate that the AT1 receptor exists as two isoforms, AT1A and AT1B, encoded by separate genes; AT1A predominates in blood pressure regulation and neuroendocrine control, whereas AT1B generally plays a compensatory or tissue-restricted role^[4][7][8]. For experimental applications, selective AT1 receptor antagonists are widely used to suppress pathological angiotensin II signaling and to investigate receptor-dependent mechanisms underlying cardiovascular, renal, and inflammatory disorders^[1][6].