Relationship of cellular calcium to salt sensitivity in patients with essential hypertension

The significance of cellular calcium metabolism and systemic calcium balance in sodium chloride sensitivity was studied in 16 patients with essential hypertension and in 13 normotensive subjects. With changes in sodium chloride intake from 3 to 20 g/day, mean blood pressure, lymphocyte [Ca2+]i and the acute hypotensive response to nifedipine were increased in the hypertensive patients, but not in the normotensive subjects. Serum calcium concentration was decreased and urinary calcium excretion was increased in both groups. In the hypertensive patients, elevation of mean blood pressure was positively correlated with the increase in lymphocyte [Ca2+]i and with the enhancement of the hypotensive response to nifedipine, but it was not related to the change in serum or urinary calcium. These results suggest that enhancement of cellular-calcium-dependent vasoconstriction may lead to increased blood pressure following sodium chloride loading in patients with essential hypertension.