Angiotensin II receptor type 1

Angiotensin II receptor, type 1 or AT₁ receptor is the best characterized angiotensin receptor. It has vasopressor effects and regulates aldosterone secretion. It is an important effector controlling blood pressure and volume in the cardiovascular system. Angiotensin II receptor antagonists are drugs indicated for hypertension, diabetic nephropathy and congestive heart failure.

Function

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.

Mechanism

The angiotensin receptor is activated by the vasoconstricting peptide angiotensin II. The activated receptor in turn couples to G_q/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.

Clinical significance

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

The AT₁ receptor has also been implicated in post-traumatic stress disorder,

Animal studies

AT₁ receptor antagonists have been shown to reduce fear memory recall in mice.

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.

Interactions

Angiotensin II receptor type 1 has been shown to interact with Zinc finger and BTB domain-containing protein 16. The protein's mRNA has been reported to interact with Mir-132 microRNA as part of an RNA silencing mechanism that reduces receptor expression.

External links

This article incorporates text from the United States National Library of Medicine, which is in the public domain.