Reduction of cerebral NaCl concentration can abolish mineralocorticoid escape

Abstract

The effect of lowering cere-brospinal fluid (CSF) Na concentration on renal Na excretion (UNaV̇) was investigated in conscious sheep undergoing mineralocorticoid escape induced by intravenous infusion of aldosterone (20 μg · ml-1 · h-1) for 3 days. On the 3rd day of aldoster-one administration, when plasma and CSF Na concentration and mean arterial blood pressure (MABP) were increased as a result of the mineralocorticoid treatment, a reduction in the CSF Na concentration was induced by infusing a Na-free solution of 300 mmol/1 mannitol (1 ml/h) into a lateral cerebral ventricle. This caused significant reductions in UNaV̇ and MABP and a significant increase in renal free water clearance (CH2..