title: 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 microliters), and cerebrospinal fluid was collected by continuous 24-hour withdrawal (200 microliters/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 less than 0.05) over 24 hours in DS rats and remained at about that level until the NaCl was increased to 8%, which resulted in a gradual rise of mean arterial pressure over the next 7 days to 135 mm Hg. Cerebrospinal fluid sodium was unchanged in DR and Sprague-Dawley rats fed 4% or 8% sodium, but in DS rats rose from 152.3 to 155.2 +/- 0.6 meq/l on the third day at 4% sodium and remained elevated over the next 2 weeks of study. Blood sodium was unchanged throughout the study in all groups. On the first day only of the 4% and 8% sodium diets, both DS and DR rats exhibited a similar net retention of sodium, which was greater than the Sprague-Dawley rats (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Physiology, Medical College of Wisconsin, Milwaukee 53226.
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: A W
authors.initials: AW
authors.lastname: Cowley
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004198:Disease Susceptibility; D005260:Female; D006973:Hypertension / Q000134:cerebrospinal fluid* / Q000209:etiology / Q000503:physiopathology; D066298:In Vitro Techniques; D008297:Male; D009318:Natriuresis / Q000187:drug effects; D011188:Potassium / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains / Q000134:cerebrospinal fluid*; D012964:Sodium / Q000097:blood / Q000134:cerebrospinal fluid*; D012982:Sodium, Dietary / Q000008:administration & dosage; D014882:Water-Electrolyte Balance / Q000187:drug effects
chemical_list: D012982:Sodium, Dietary; D012964:Sodium; D011188:Potassium