Effect of dietary sodium intake on intracellular calcium in lymphocytes of salt-sensitive hypertensive patients.
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)
Alexiewicz
J M
JM
Department of Medicine, University of Southern California, Los Angeles.
Gaciong
Z
Z
Parise
M
M
Karubian
F
F
Massry
S G
SG
Campese
V M
VM
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000032:analysis* / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D002469:Cell Separation; D003600:Cytosol / Q000737:chemistry; D003692:Delayed-Action Preparations; D005260:Female; D006801:Humans; D006973:Hypertension / Q000378:metabolism*; D008214:Lymphocytes / Q000737:chemistry* / Q000166:cytology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009543:Nifedipine / Q000008:administration & dosage / Q000494:pharmacology; D012982:Sodium, Dietary / Q000494:pharmacology*
D015220:Calcium Channels; D003692:Delayed-Action Preparations; D012982:Sodium, Dietary; D009543:Nifedipine; D002118:Calcium