Angiotensin I-converting enzyme inhibitors are allosteric enhancers of kinin B1 and B2 receptor function.
The beneficial effects of angiotensin I-converting enzyme (ACE) inhibitors go beyond the inhibition of ACE to decrease angiotensin (Ang) II or increase kinin levels. ACE inhibitors also affect kinin B1 and B2 receptor (B1R and B2R) signaling, which may underlie some of their therapeutic usefulness. They can indirectly potentiate the actions of bradykinin (BK) and ACE-resistant BK analogs on B2Rs to elevate arachidonic acid and NO release in laboratory experiments. Studies indicate that ACE inhibitors and some Ang metabolites increase B2R functions as allosteric enhancers by inducing a conformational change in ACE. This is transmitted to B2Rs via heterodimerization with ACE on the plasma membrane of cells. ACE inhibitors are also agonists of the B1R, at a Zn-binding sequence on the second extracellular loop that differs from the orthosteric binding site of the des-Arg-kinin peptide ligands. Thus, ACE inhibitors act as direct allosteric B1R agonists. When ACE inhibitors enhance B2R and B1R signaling, they augment NO production. Enhancement of B2R signaling activates endothelial NO synthase, yielding a short burst of NO; activation of B1Rs results in a prolonged high output of NO by inducible NO synthase. These actions, outside inhibiting peptide hydrolysis, may contribute to the pleiotropic therapeutic effects of ACE inhibitors in various cardiovascular disorders.
Erdös
Ervin G
EG
Department of Pharmacology, University of Illinois College of Medicine, Chicago, Ill 60612, USA. egerdos@uic.edu
Tan
Fulong
F
Skidgel
Randal A
RA
D000494:Allosteric Regulation / Q000187:drug effects / Q000502:physiology; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D000818:Animals; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D021381:Protein Transport / Q000187:drug effects; D043783:Receptor, Bradykinin B1 / Q000187:drug effects / Q000378:metabolism*; D043782:Receptor, Bradykinin B2 / Q000187:drug effects / Q000378:metabolism*; D012680:Sensitivity and Specificity; D015398:Signal Transduction / Q000187:drug effects
D000806:Angiotensin-Converting Enzyme Inhibitors; D043783:Receptor, Bradykinin B1; D043782:Receptor, Bradykinin B2; D019001:Nitric Oxide Synthase