Effect of dietary sodium intake on intracellular calcium in lymphocytes of salt-sensitive hypertensive patients

Am J Hypertens. 1992 Aug;5(8):536-41. doi: 10.1093/ajh/5.8.536.

Abstract

High dietary Na+ raises mean arterial pressure (MAP) by more than 10% in salt-sensitive (SS) patients with essential hypertension. To test whether the rise in MAP in these patients is caused by a Na(+)-linked increase in [Ca2+]i in vascular smooth muscle cells, we measured [Ca2+]i in the lymphocytes of 14 patients with essential hypertension kept on a Na+ intake of 20 mEq/day for 9 days, and 200-mEq/day for 14 days. Nifedipine gastrointestinal transport system (GITS) (30 mg/day) was given during the last 4 days of each diet. We isolated lymphocytes on Ficoll-Hypaque gradient and measured [Ca2+]i levels using Fura-2 fluorescent dye. During low Na+ intake, there was no difference in MAP (102 +/- 3.5 v 93 +/- 3.8 mm Hg) and in lymphocytes [Ca2+]i (80 +/- 3.0 v 87 +/- 5.4 nmol/L) between the seven salt-sensitive and the seven salt-resistant patients. During high Na+ intake, MAP (92 +/- 2.8 mm Hg) and [Ca2+]i (85 +/- 6.8 nmol/L) did not change in salt-resistant patients. On the contrary, MAP (115 +/- 3.4 mm Hg) and [Ca2+]i (130 +/- 11.1 nmol/L) increased significantly (P less than .01) in the salt-sensitive patients. Nifedipine did not significantly alter MAP and [Ca2+]i in both groups of patients during low Na+ and in salt-resistant patients during high Na+ intake. On the contrary, during high Na+ intake, nifedipine decreased significantly (P less than .01) both MAP (104 +/- 2.4 mm Hg) and [Ca2+]i (89 +/- 5.7 nmol/L) in salt-sensitive patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Blood Pressure / drug effects
  • Blood Pressure / physiology
  • Calcium / analysis*
  • Calcium / metabolism
  • Calcium Channels / drug effects
  • Calcium Channels / physiology
  • Cell Separation
  • Cytosol / chemistry
  • Delayed-Action Preparations
  • Female
  • Humans
  • Hypertension / metabolism*
  • Lymphocytes / chemistry*
  • Lymphocytes / cytology*
  • Lymphocytes / metabolism
  • Male
  • Middle Aged
  • Nifedipine / administration & dosage
  • Nifedipine / pharmacology
  • Sodium, Dietary / pharmacology*

Substances

  • Calcium Channels
  • Delayed-Action Preparations
  • Sodium, Dietary
  • Nifedipine
  • Calcium