Angiotensin-(1–7) stimulates water transport in rat inner medullary collecting duct: evidence for involvement of vasopressin V2 receptors

Abstract

The peptide angiotensin-(1-7) [Ang-(1-7)] is known to enhance water transport in rat inner medullary collecting duct (IMCD). The aim of this study was to determine the mechanism of the Ang-(1-7) effect on osmotic water permeability (Pf). Pf was measured in the normal rat IMCD perfused in vitro in presence of agonists [Ang-(1-7), arginine vasopressin (AVP) and Ang-(3-8)], and antagonists of the angiotensin and the vasopressin cascade. Ang-(1-7), but not Ang-(3-8), increased Pf significantly. The effect of Ang-(1-7) on Pf was abolished by its selective antagonist, A-779, added before or after Ang-(1-7). Prostaglandin E2 and the protein kinase A inhibitor H8 also blocked the Ang-(1-7) effect. Blockade of vasopressin V1 receptors by antagonists did not change the Ang-(1-7) effect, but pre-treatment with a V2 antagonist abolished the effect of Ang-(1-7) on Pf. Similarly, pre-treatment with A-779 inhibited AVP's effect on Pf. Forskolin-stimulated Pf was blocked both by A-779 and by the V2 antagonist. Finally, Ang-(1-7) increased cAMP levels in fresh IMCD cell suspensions whilst the forskolin-stimulated cAMP synthesis was decreased by A-779 and the V2 antagonist. These data provide evidence that Ang-(1-7) interacts via its receptor with the AVP V2 system through a mechanism involving adenylate-cyclase activation.

Development of hepatorenal syndrome in bile duct ligated rats

“…It has been clearly demonstrated that angiotensin-(1-7) also exerts complex renal actions [19,21,22] . Our group and others detected in vivo and in vitro antidiuretic effects of angiotensin-(1-7) by increasing fluid reabsorption [23][24][25][26] . These renal actions could contribute to sodium and water retention observed in bile duct ligated rats.…”

Nonpeptide AVE 0991 Is an Angiotensin-(1–7) Receptor Mas Agonist in the Mouse Kidney

“…13 Moreover, it was demonstrated recently that Ang-(1-7) but not Ang IV produces a significant dose-dependent increase in water permeability in the IMCDs accompanied by an increase in cAMP levels. 12 A-779 completely blocked these effects, suggesting a specific receptor-mediated action. 12 Interestingly, pretreatment with an AVP V 2 -receptor antagonist inhibited the Ang-(1-7) effect on water permeability.…”

“…12 A-779 completely blocked these effects, suggesting a specific receptor-mediated action. 12 Interestingly, pretreatment with an AVP V 2 -receptor antagonist inhibited the Ang-(1-7) effect on water permeability. Similarly, A-779 inhibited the effect of AVP on water transport.…”

ANG II, ANG-(1-7), ALDO and AVP biphasic effects on Na+/H+ transport: the role of cellular calcium

“…In addition, in normal and hypertensive rats [177] and in water-loaded [178] or virgin female rats [179], ANG-(1-7) had an antidiuretic effect that was mediated, at least in part, by the Mas receptor. Furthermore, in SpragueDawley rats, the administration of ANG-(1-7) resulted in antidiuresis that was associated with an upregulation in renal aquaporin-1 [180], and in isolated rat inner medullary collecting duct cell suspensions, ANG-(1-7) (10 −9 M) increased cAMP production [181], a response that was attenuated by Mas receptor antagonists and the pharmacological blockade of the AVP V2 receptor. ANG-(1-7) also caused afferent arteriolar vasodilation and antagonized the vasoconstrictor effects of ANG II [114].…”

“…Thus, whether one or more different signaling systems are involved in mediating the effect of ANG-(1-7) on NHE3 activity in the S2 and S3 proximal segments remains to be established. In addition, the renal effects of ANG-(1-7) may also involve AT1 and AT2 receptors [182, 184,186] and V2 receptors [181], indicating the existence of a cross-talk mechanism between the Mas receptor and the ANG II and AVP systems. Furthermore, in a study of isolated rat proximal straight tubules [183], the actions of ANG-(1-7) were blocked by an AT1 antagonist, suggesting a different site of action than the one that was assessed in the in vivo rat proximal convoluted tubules study [191].…”