Abstract P284: Neuron Specific (Pro)renin Receptor Knockout Reduces Sodium Appetite and Attenuates the Development of DOCA-salt Induced Hypertension

Abstract

The (pro) renin receptor (PRR) is a key component of the renin-angiotensin system that is highly expressed in the brain. We previously showed that the neuronal PRR deletion attenuates deoxycorticosterone acetate (DOCA)-salt induced hypertension. However, the mechanism underlying remains unclear. To test our hypothesis that PRR is involved in the regulation of sodium appetite during DOCA-salt hypertension, we used a neuron-specific PRR knockout (PRRKO) mouse model generated using the Cre-LoxP system. The PRRKO and their wildtype controls (WT) were implanted with 50 mg DOCA pellet with free access to regular water and 0.9 % saline as the drinking solution. Blood pressure (BP) was monitored by telemetry system in conscious free moving mice. The fluid intake and urine output were monitored along 21 days of DOCA-Salt treatment. The BP is significantly lower in PRRKO compared with WT mice following 21 days of DOCA-salt treatment (112 ± 2 vs. 134 ± 7 mmHg, P= 0.0186). Interestingly, we found that saline intake (27.8 ± 1.8 vs. 15.9 ± 1.2 ml/day, P=0.0007) and total fluid intake (31.1 ± 1.9 vs. 21.1 ± 1.4 ml/day, P=0.003) were higher; while the regular water intake was lower (3.4 ± 0.6 vs. 5.2 ± 0.3 ml/day, P=0.03) in WT compared to PRRKO mice. PRR deletion in the neurons reduced sodium appetite presented as the ratio of saline intake over total fluid intake (0.75 ± 0.016 vs. 0.89 ± 0.019, P=0.0005), as well as total sodium intake (2.45 ± 0.19 vs. 4.28 ± 0.28 mmol/day, P=0.0007) compared with WT mice at the end of the protocol. In addition, the urinary sodium excretion was lower (13.3±1.17 vs. 20±1.17 mmol/day, P<0.0001), but not potassium excretion (0.64 ± 0.028 vs. 0.56 ± 0.05 mmol/day, P=0.1291) in PRRKO compared with WT mice; however, there is no difference in urine sodium and potassium concentrations. Furthermore, plasma vasopressin level (19.0 ± 2.7 vs. 33.6 ± 2.7 pg/ml, P=0.0037) is lower in the PRRKO compared with WT mice at the end of DOCA-salt treatment. In summary, PRR deletion in the neurons reduced sodium appetite, circulating vasopressin level, and attenuated the development of DOCA-salt induced hypertension. Taken together, the present findings suggest that PRR regulates the BP and plays a key role in salt-sensitive hypertension, at least in part, by modulating sodium appetite.