Effect of antihypertensive treatment on intracellular calcium concentration and intracellular pH in essential hypertension.
The platelet intracellular calcium concentration ([Ca2+]i) and intracellular pH (pHi) were measured by spectrofluorimetry with the dyes Fura-2 and BCECF, respectively, in 19 patients with essential hypertension (10 males), aged 48 +/- 2 years, before and after 12 weeks of antihypertensive treatment and in 19 normotensive controls (11 males), aged 46 +/- 3 years. [Ca2+]i and pHi were measured in the resting state and after stimulation in vitro with 0.1 U/ml human thrombin. In patients with essential hypertension, both resting [Ca2+]i (61 +/- 4 nmol/l) and thrombin-induced maximal increase in [Ca2]i (291 +/- 26 nmol/l) were significantly (P < 0.01) greater than in the normotensive controls (resting 49 +/- 2 nmol/l and thrombin-induced 199 +/- 21 nmol/l). With respect to pHi, no difference in resting pHi between both groups was found (7.16 +/- 0.01 vs. 7.16 +/- 0.01). However, pHi increment at 300 seconds in response to thrombin was higher in the patients with essential hypertension than in the controls (0.131 +/- 0.02 vs. 0.083 +/- 0.01 pH units, P < 0.05). The increment in pHi was blunted by the amiloride derivative EIPA, indicating that it was mediated by the Na+/H+ exchanger. After antihypertensive therapy in the essential hypertensive patients, basal [Ca2+]i was significantly reduced (52 +/- 2 nmol/l, P < 0.01) and was not statistically different to the value found in the normotensive controls. Resting pHi suffered no significant modification after treatment (7.17 +/- 0.01, P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)
Poch
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E
Nephrology Service, Hospital Clinic I Provincial, University of Barcelona, Catalonia, Spain.
Botey
A
A
Gaya
J
J
Darnell
A
A
Rivera
F
F
Revert
L
L
D000328:Adult; D000959:Antihypertensive Agents / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism*; D002118:Calcium / Q000097:blood*; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D006973:Hypertension / Q000097:blood* / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D017923:Sodium-Hydrogen Exchangers / Q000097:blood; D013050:Spectrometry, Fluorescence
D000959:Antihypertensive Agents; D017923:Sodium-Hydrogen Exchangers; D002118:Calcium