Figure 615

Subclasses of angiotensin receptors. Another theoretic reason the actions of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II (AII) receptor antagonists may differ. All of the AII receptor antagonists currently available for clinical use selectively block the AT 1 receptor. This receptor appears to transduce most of the well-known effects of AII, including vasoconstriction, stimulation of cell growth, and secretion of aldosterone. Increasingly, however, potentially important actions of other angiotensin receptors are being discovered. For example, AT2 receptors may be involved in regulation of apoptosis and modulation of inflammation by way of secretion of RANTES (see Fig. 6-13) [13,15]. AT4 receptors bind other angiotensins preferentially and may promote endothelially mediated vasodilatation [16]. Activity of all pathways is reduced after administration of ACE inhibitors, whereas only AT1 receptor-mediated events are blocked by drugs currently available. Whether these differences will have important consequences for progression of renal disease is currently unknown.

0 0

Post a comment