Angiotensin II receptor type 1

Angiotensin II receptor, type 1 or AT1 receptor is an angiotensin receptor. It has vasopressor effects and regulates aldosterone secretion. It is an important effector controlling blood pressure and volume in the cardiovascular system.

It is the best elucidated angiotensin receptor.

Mechanism
The angiotensin receptor is activated by the vasoconstricting peptide angiotensin II. The activated receptor in turn couples to Gq/11 and thus activates phospholipase C and increases the cytosolic Ca2+ concentrations, which in turn triggers cellular responses such as stimulation of protein kinase C. Activated receptor also inhibits adenylate cyclase and activates various tyrosine kinases.

Effects
The AT1 receptor mediates the major cardiovascular effects of angiotensin II. Effects include vasoconstriction, aldosterone synthesis and secretion, increased vasopressin secretion, cardiac hypertrophy, augmentation of peripheral noradrenergic activity, vascular smooth muscle cells proliferation, decreased renal blood flow, renal renin inhibition, renal tubular sodium reuptake, modulation of central sympathetic nervous system activity, cardiac contractility, central osmocontrol and extracellular matrix formation.

Pathology
The AT1 receptor may play role in the generation of reperfusion arrhythmias following restoration of blood flow to ischemic or infarcted myocardium.

Gene
It was previously thought that a related gene, denoted as AGTR1B, existed; however, it is now believed that there is only one type 1 receptor gene in humans. At least four transcript variants have been described for this gene. Additional variants have been described but their full-length nature has not been determined. The entire coding sequence is contained in the terminal exon and is present in all transcript variants.