Angiotensin receptors: signaling, vascular pathophysiology, and interactions with ceramide

C Berry, R Touyz, AF Dominiczak… - American Journal …, 2001 - journals.physiology.org
C Berry, R Touyz, AF Dominiczak, RC Webb, DG Johns
American Journal of Physiology-Heart and Circulatory Physiology, 2001journals.physiology.org
Angiotensin II (ANG II) is a pleiotropic vasoactive peptide that binds to two distinct receptors:
the ANG II type 1 (AT1) and type 2 (AT2) receptors. Activation of the renin-angiotensin
system (RAS) results in vascular hypertrophy, vasoconstriction, salt and water retention, and
hypertension. These effects are mediated predominantly by AT1 receptors. Paradoxically,
other ANG II-mediated effects, including cell death, vasodilation, and natriuresis, are
mediated by AT2 receptor activation. Our understanding of ANG II signaling mechanisms …
Angiotensin II (ANG II) is a pleiotropic vasoactive peptide that binds to two distinct receptors: the ANG II type 1 (AT1) and type 2 (AT2) receptors. Activation of the renin-angiotensin system (RAS) results in vascular hypertrophy, vasoconstriction, salt and water retention, and hypertension. These effects are mediated predominantly by AT1 receptors. Paradoxically, other ANG II-mediated effects, including cell death, vasodilation, and natriuresis, are mediated by AT2 receptor activation. Our understanding of ANG II signaling mechanisms remains incomplete. AT1receptor activation triggers a variety of intracellular systems, including tyrosine kinase-induced protein phosphorylation, production of arachidonic acid metabolites, alteration of reactive oxidant species activities, and fluxes in intracellular Ca2+concentrations. AT2 receptor activation leads to stimulation of bradykinin, nitric oxide production, and prostaglandin metabolism, which are, in large part, opposite to the effects of the AT1 receptor. The signaling pathways of ANG II receptor activation are a focus of intense investigative effort. We critically appraise the literature on the signaling mechanisms whereby AT1 and AT2 receptors elicit their respective actions. We also consider the recently reported interaction between ANG II and ceramide, a lipid second messenger that mediates cytokine receptor activation. Finally, we discuss the potential physiological cross talk that may be operative between the angiotensin receptor subtypes in relation to health and cardiovascular disease. This may be clinically relevant, inasmuch as inhibitors of the RAS are increasingly used in treatment of hypertension and coronary heart disease, where activation of the RAS is recognized.
American Physiological Society