title: Myocardial (Na+,K+)-ATPase activity in Dahl salt-sensitive and resistant rats.
abstract: Vascular (Na+,K+)-pump activity (ouabain-sensitive 86Rb+ uptake) and myocardial (Na+,K+)-ATPase activity are reduced in animals with various forms of low renin, experimental hypertension. On the other hand, vascular (Na+,K+)-pump activity is increased in Dahl salt-sensitive relative to resistant rats (a genetic model of hypertension), regardless of salt intake or blood pressure and it is also increased in Dahl salt-sensitive rats on high salt (8% NaCl) relative to low salt (0.4% NaCl) diets. It has been suggested that this increase in vascular (Na+,K+)-pump activity may be secondary to an increase in the vascular sarcolemmal permeability to Na+ in these salt-sensitive rats. In the present study, (Na+,K+)-ATPase activity of left ventricular microsomal fractions, was increased in Dahl salt-sensitive relative to resistant rats on low salt diets; however, this difference disappeared when these salt-sensitive and resistant rats were placed on high salt diets. In contrast, myocardial (Na+,K+)-ATPase activity was decreased in Dahl salt-sensitive rats on high relative to low salt diets. Evidence that this decrease in (Na+,K+)-ATPase activity is not secondary to myocardial hypertrophy in the hypertensive salt-sensitive rats, and mechanisms by which decreased cardiovascular (Na+,K+)-pump activity, increased sarcolemmal permeability or both, might contribute to elevated blood pressure, are discussed.
authors.forename: D L
authors.initials: DL
authors.lastname: Clough
authors.forename: M B
authors.initials: MB
authors.lastname: Pamnani
authors.forename: S J
authors.initials: SJ
authors.lastname: Huot
authors.forename: F J
authors.initials: FJ
authors.lastname: Haddy
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001794:Blood Pressure; D001835:Body Weight; D017301:Ca(2+) Mg(2+)-ATPase; D006973:Hypertension / Q000201:enzymology* / Q000235:genetics; D009206:Myocardium / Q000201:enzymology*; D051381:Rats; D011918:Rats, Inbred SHR; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
chemical_list: D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; D000254:Sodium-Potassium-Exchanging ATPase