Angiotensin Receptors
The angiotensin family of peptides is important in the regulation of blood volume, vascular resistance and electrolyte balance. Angiotensin II, the main peptide of the renin-angiotensin system, produces a variety of physiological effects. It is produced in a cascade whereby the precursor peptide angiotensinogen is cleaved to produce renin and angiotensin I. Angiotensin-converting enzyme then acts on angiotensin I to yield the octapeptide angiotensin II, and further processing generates angiotensin III and IV. These peptides act on three angiotensin receptor subtypes, AT1, AT2 and AT4, the properties of which are summarized below. The actions of angiotensin II are primarily mediated by AT1, whereas AT2 preferentially binds angiotensin III and AT4 is selective for angiotensin IV.
Angiotensin Receptor Data
| Receptor Subtype | AT1 Receptors | AT2 Receptors | AT4 Receptors |
|---|---|---|---|
| Transduction Mechanism | Gq/11 | Gi/o | Unknown |
| Primary Locations | Liver, kidney, adrenal gland, lung | Brain, adrenal medulla, heart, uterus | Kidney, brain, adrenal gland, heart, liver, lung |
| Tissue Functions | Mediates vasoconstriction, regulates aldosterone and vasopressin release, salt and water retention, cell proliferation and migration, sympathetic stimulation | Counterbalances effects of the AT1 receptor | Regulates blood flow and renal tubular reabsorption, affects cardiac hypertrophy and memory acquisition |
| Selective Agonists | - | CGP 42112 (2569) | - |
| Selective Antagonists |
ZD 7155 (1211) EMD 66684 (1849) |
PD 123319 (1361) | - |
References
Gasparo et al (2000) International Union of Pharmacology XXIII. The angiotensin II receptors. Pharmacol.Rev. 52 415. Alexander et al (2000) Guide to receptors and channels. Br.J.Pharmacol. 141 Suppl.1.