The pressor effect of sodium-volume expansion is calcium mediated

J. P. Nicholson, L. M. Resnick, J. Cigarroa, D. Marion, E. D. Vaughan, J. H. Laragh

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


To investigate the calcium dependence of salt-induced hypertension we concurrently measured blood pressure and serum ionized calcium in conscious normotensive female dogs undergoing five infusions: 1) sodium chloride (0.9%) 2) calcium chloride (10 μg/kg), 3) combined sodium chloride and calcium chloride, 4) nicardipine (1μg/kg/min), and 5) combined sodium chloride and calcium chloride in the presence of nicardipine.While saline and calcium chloride infusions individually did not affect blood pressure, saline combined with calcium chloride significantly and consistently raised mean arterial pressure (MAP) (AMAP = 7 ± 2 mm Hg, P <.001 v baseline).Serum ionized calcium (Caio) levels increased within the normal range with the infusion of calcium alone (1.32 ± 0.03 to 1.48 ± 0.01 mmol/L, P <.005). Extracellular Caio rose less with the combined NaCl-CaClj infusion (ACaio 0.10 ± 0.01 v 0.16 ± 0.02 mmol/L, P <.02). The difference in calcium elevations could not be attributed to volume expansionalone, since saline infusion itself did not affect serum ionized calcium (1.32 ± 0.3 to 1.31 ± 0.01 mmol/L, P = NS). Furthermore, nicardipine prevented the pressor effect of the combined saline-calcium infusion. (AMAP = — 2±3z>7±2 mm Hg, P <.001), and restored the rise in extracellular Caio to that seen with the nonpressor calcium infusion (ACaio 0.15 ± 0.01 mmol/L v 0.16 ± 0.02 mmol/L, P = NS). Altogether, these data demonstrate that the rise in blood pressure and ionized calcium following an acute infusion of sodium and calcium chloride are interdependent. They further suggest the critical importance of cellular calcium uptake from the extracellular space as at least one mechanism by which sodium loading may elevate blood pressure.

Original languageEnglish (US)
Pages (from-to)904-908
Number of pages5
JournalAmerican Journal of Hypertension
Issue number11
StatePublished - Nov 1991
Externally publishedYes


  • Blood pressure
  • Calcium chloride
  • Dogs
  • Nicardipine
  • Serum ionized calcium
  • Sodium chloride

ASJC Scopus subject areas

  • Internal Medicine


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