The renin-angiotensin system in hypertension, a constantly renewing classic: Focus on the angiotensin AT2-receptor

It is common knowledge that the renin-angiotensin system (RAS), in particular angiotensin II acting through the angiotensin AT1-receptor (AT1R), is pivotal for the regulation of blood pressure (BP) and extracellular volume. More recent findings have revealed that the RAS is far more complex than initially thought and that it harbours additional mediators and receptors, which are able to counteract and thereby fine-tune AT1R-mediated actions. This review will focus on the angiotensin AT2-receptor (AT2R), which is one of the “counter-regulatory” receptors within the RAS. It will review and discuss data related to the role of the AT2R in regulation of BP and focus on the following 3 questions: Do peripheral AT2R have an impact on BP regulation, and, if so, does this effect become apparent only under certain conditions? Are central nervous system AT2R involved in regulation of BP, and, if so, which brain areas are involved and what are the mechanisms? Does dysfunction of AT2R contribute to the pathogenesis of hypertension in preeclampsia?