title: Effects of diltiazem on cation transport across erythrocyte membranes of hypertensive humans.
abstract: The effects of the calcium antagonist diltiazem on diastolic blood pressure and various parameters of erythrocyte membrane cation transport were evaluated in hypertensive patients with diastolic blood pressure between 95 and 110 mm Hg in a placebo-controlled, double-blind parallel study. Twenty-one patients completed the study; 13 received placebo, while 8 received diltiazem. Diastolic blood pressure, intracellular sodium and calcium concentrations, ouabain-sensitive Na+,K+-adenosine triphosphatase (ATPase) activity, and net sodium efflux and potassium influx across red blood cell membranes were examined in both groups at the end of placebo run-in, at the end of the titration phase, and at the completion of study. In the placebo group, none of the parameters changed significantly. In the drug-treated group, diastolic blood pressure declined by approximately 10% (placebo, 95.1 +/- 8.9; drug-treated, 86.9 +/- 4.9 mm Hg; p less than 0.03) at the end of the study. There were also reductions in intracellular sodium (placebo, 7.9 +/- 1.8; drug-treated, 5.2 +/- 0.4 mmol/L cells; p less than 0.002) and calcium (placebo, 13.5 +/- 1.6; drug-treated 10.8 +/- 3.3 mumol/L cells; p less than 0.03) concentrations, accompanied by a simultaneous rise in the activity of the ouabain-sensitive Na+,K+-ATPase of erythrocyte membranes (placebo, 7.1 +/- 1.1 X 10(-2); drug-treated, 9.0 +/- 0.6 X 10(-2) microM inorganic phosphate/hr/mg; p less than 0.001) at the end of the study. However, no significant change in the ouabain-insensitive moiety of the ATPase pump was found. Diltiazem treatment increased net sodium efflux and potassium influx.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D001794:Blood Pressure / Q000187:drug effects; D004110:Diltiazem / Q000627:therapeutic use*; D004311:Double-Blind Method; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000378:metabolism; D007473:Ion Channels / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000378:metabolism; D011897:Random Allocation; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism
chemical_list: D007473:Ion Channels; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D004110:Diltiazem; D011188:Potassium