Sodium-, potassium-, chloride-, and bicarbonate-related effects on blood pressure and electrolyte homeostasis in deoxycorticosterone acetate-treated rats.
Na(+) loading without Cl(-) fails to increase blood pressure in the DOCA model. We compared the changes in the total body (TB) effective Na(+), K(+), Cl(-), and water (TBW) content as well as in intracellular (ICV) or extracellular (ECV) volume in rats receiving DOCA-NaCl, DOCA-NaHCO(3), or DOCA-KHCO(3). We divided 42 male rats into 5 groups. Group 1 was untreated, group 2 received 1% NaCl, and groups 3, 4, and 5 were treated with DOCA and received 1% NaCl, 1.44% NaHCO(3), or 1.7% KHCO(3) to drink. We measured mean arterial blood pressure (MAP) directly after 3 wk. Tissue electrolyte and water content was measured by chemical analysis. Compared with control rats, DOCA-NaCl increased MAP while DOCA-NaHCO(3) and DOCA-KHCO(3) did not. DOCA-NaCl increased TBNa(+) 26% but only moderately increased TBW. DOCA-NaHCO(3) led to similar TBNa(+) excess, while TBW and ICV, but not ECV, were increased more than in DOCA-NaCl rats. DOCA-KHCO(3) did not affect TBNa(+) or volume. At a given TB(Na(+)+K(+)) and TBW, MAP in DOCA-NaCl rats was higher than in control, DOCA-NaHCO(3), and DOCA-KHCO(3) rats, indicating that hypertension in DOCA-NaCl rats was not dependent on TB(Na(+)+K(+)) and water mass balance. Skin volume retention was hypertonic compared with serum and paralleled hypertension in DOCA-NaCl rats. These rats had higher TB(Na(+)+K(+))-to-TBW ratio in accumulated fluid than DOCA-NaHCO(3) rats. DOCA-NaCl rats also had increased intracellular Cl(-) concentrations in skeletal muscle. We conclude that excessive cellular electrolyte redistribution and/or intracellular Na(+) or Cl(-) accumulation may play an important role in the pathogenesis of salt-sensitive hypertension.
Ziomber
Agata
A
Department of Nephrology and Hypertension, Nikolaus-Fiebiger Center for Molecular Medicine, Glückstr. 6, 91054 Erlangen, Germany.
Machnik
Agnes
A
Dahlmann
Anke
A
Dietsch
Peter
P
Beck
Franz-Xaver
FX
Wagner
Hubertus
H
Hilgers
Karl F
KF
Luft
Friedrich C
FC
Eckardt
Kai-Uwe
KU
Titze
Jens
J
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001834:Body Water / Q000378:metabolism; D002712:Chlorides / Q000097:blood / Q000494:pharmacology*; D003900:Desoxycorticosterone / Q000494:pharmacology*; D004573:Electrolytes / Q000378:metabolism; D006706:Homeostasis; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D011188:Potassium / Q000097:blood / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000187:drug effects; D012879:Skin Physiological Phenomena / Q000187:drug effects; D012964:Sodium / Q000097:blood / Q000494:pharmacology*
D002712:Chlorides; D004573:Electrolytes; D003900:Desoxycorticosterone; D012964:Sodium; D011188:Potassium