Role of renin-angiotensin-aldosterone system in salt-sensitive hypertension induced by sensory denervation.

To define the role of the renin-angiotensin-aldosterone system in a novel salt-sensitive model, neonatal Wistar rats were given capsaicin (50 mg/kg sc) on the first and second days of life. After weaning, male rats were divided into the following six groups and treated for 3 wk with: control + normal sodium diet (CON-NS), CON + high-sodium diet (CON-HS), CON + HS + spironolactone (50 mg x kg(-1) x day(-1), CON-HS-SP), capsaicin pretreatment + NS (CAP-NS), CAP-HS, and CAP-HS-SP. Radioimmunoassay shows that plasma renin activity (PRA) and plasma aldosterone level (PAL) were suppressed by HS, but they were higher in CAP-HS than in CON-HS and CON-HS-SP (P < 0.05). Both tail-cuff systolic blood pressure and mean arterial pressure were higher in CAP-HS than in all other groups (P < 0.05). Urine water and sodium excretion were increased with HS intake, but they were lower in CAP-HS than in CON-HS (P < 0.05). Western blot did not detect differences in adrenal AT1 receptor content. Therefore, insufficiently suppressed PRA and PAL in response to HS intake by sensory denervation may contribute to increased salt sensitivity and account for effectiveness of spironolactone in lowering blood pressure in this model.