Abstract
The renin-angiotensin-aldosterone and arginine vasopressin-V2 receptor-aquaporin-2 (AQP2) systems converge on the epithelial Na+channel (ENaC) to regulate blood pressure and plasma tonicity. Although it is established that V2 receptors initiate renal water reabsorption through AQP2, whether V2 receptors can also induce renal Na+retention through ENaC and raise blood pressure remains an open question. We hypothesized that a specific increase in V2 receptor-mediated ENaC activity can lead to high blood pressure. Our approach was to test effects of chronic activation of V2 receptors in Liddle mice, a genetic mouse model of high ENaC activity, and compare differences in ENaC activity, urine Na+excretion, and blood pressure with control mice. We found that ENaC activity was elevated in Liddle mice and could not be stimulated further by administration of desmopressin (dDAVP), a V2 receptor-specific agonist. In contrast, Liddle mice showed higher levels of expression of AQP2 and aquaporin-3, but they could still respond to dDAVP infusion by increasing phospho-AQP2 expression. With dDAVP infusion, Liddle mice excreted smaller urine volume and less urine Na+and developed higher blood pressure compared with control mice; this hypertension was attenuated with administration of the ENaC inhibitor benzamil. We conclude that V2 receptors contribute to hypertension in the Liddle mouse model by promoting primary Na+and concomitant water retention. NEW & NOTEWORTHY Liddle syndrome is a classic model for hypertension from high epithelial Na+channel (ENaC) activity. In the Liddle mouse model, vasopressin-2 receptors stimulate both ENaC and aquaporin-2, which increases Na+and water retention to such an extent that hypertension ensues. Liddle mice will preserve plasma tonicity at the expense of a higher blood pressure; these data highlight the inherent limitation in which the kidney must use ENaC as a pathway to regulate both plasma tonicity and blood pressure.
Original language | English (US) |
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Pages (from-to) | F468-F478 |
Journal | American Journal of Physiology - Renal Physiology |
Volume | 323 |
Issue number | 4 |
DOIs | |
State | Published - Oct 2022 |
Keywords
- Liddle syndrome
- collecting duct
- epithelial Nachannel
- vasopressin
- vasopressin-2 receptor
ASJC Scopus subject areas
- Physiology
- Urology