Sequential changes of cerebrospinal fluid sodium during the development of hypertension in dahl rats

Abstract

The role of sodium retention and consequent changes in cerebrospinal fluid sodium concentration in the genesis of hypertension in Dahl rats was evaluated. Dahl salt-sensitive (DS, n=7), Dahl salt-resistant (DR, n=7), and Sprague-Dawley (n=6) rats were housed in metabolic cages and instrumented with a stainless steel cannula in the cisterna magna and a femoral arterial catheter. A blood sample was drawn daily (200 μl), and cerebrospinal fluid was collected by continuous 24-hour withdrawal (200 μl/day). Daily sodium, potassium, and water balances were also determined. Rats were studied sequentially on 0.4%, 4%, and 8% sodium diets (7 days per sodium level). Mean arterial pressure increased with 4% NaCl from 107 to 120 mm Hg (p