AT1 Receptor
Full Name: Angiotensin II Type 1 Receptor (AT1 receptor)
Location:
- Vascular smooth muscle
- Heart (myocytes, fibroblasts)
- Kidney (glomeruli, proximal tubule, efferent arteriole)
- Adrenal cortex (zona glomerulosa)
- Brain (CNS cardiovascular centers)
Function / Mechanism:
The AT1 receptor mediates most of the classical effects of angiotensin II:
| Effect | Organ / System | Clinical Relevance |
|---|---|---|
| Vasoconstriction | Vascular smooth muscle | ↑ Blood pressure; target for antihypertensives |
| Aldosterone secretion | Adrenal cortex | ↑ Na⁺ & water retention; ↑ BP; contributes to HF & CKD progression |
| Sympathetic activation | CNS & heart | ↑ HR, peripheral resistance |
| Cardiac remodeling | Heart | Hypertrophy, fibrosis → contributes to HF |
| Renal effects | Efferent arterioles | Maintains GFR; chronic activation → kidney injury |
Clinical Pharmacist Pearls
- ARBs block AT1 receptors → prevent vasoconstriction, aldosterone secretion, and pathological remodeling.
- ACE inhibitors reduce Ang II levels, indirectly reducing AT1 receptor stimulation, but also affect bradykinin.
- Blocking AT1 does not affect AT2 receptors, which may mediate vasodilation and anti-fibrotic effects.
- Important in HF, CKD, post-MI, and hypertension management.
- Drug interactions / cautions: hyperkalemia risk ↑ with K⁺-sparing diuretics, caution in renal artery stenosis.
