Na-Ca exchange is proposed to be an important regulator of myoplasmic intracellular Ca concentration ([Ca]|) and contraction in vascular smooth muscle. We investigated the role of Na-Ca exchange in regulating [Ca], in swine carotid arterial tissues that were loaded with aequorin to allow simultaneous measurement of [Ca], and force. Reversal of Na-Ca exchange, by reduction of extracellular Na co...

1. The effect of purified bovine parathyroid hormone on renal tubular reabsorption of sodium and calcium has been studied by micropuncture in intact and recently thyroparathyroidectomized dogs. 2. Parathyroid hormone increased the rejection of sodium and calcium proportionately at the late proximal tubule in both intact and operated dogs. 3. In both groups of dogs, there was increased delivery ...

The participation of Na+ in regulation of intracellular Ca++ content and in formation of spontaneous action potentials of guinea-pig ureter was studied. It was shown that the fast decrease of intracellular Ca++ in the Ca(++)-loaded muscles was accompanied by enhancement of Na+ content in the cells. The concentration gradient of Na+ was found to define the effectiveness of Ca(++)-extrusion from ...

Alterations in cellular Ca and Na regulation play a role in the pathogenesis of essential hypertension. Using peripheral lymphocytes from 68 normal persons, we observed the following relationships for major cellular Ca regulatory parameters. Among men and women, Na-Ca exchanger activity was positively correlated with the resting cytosolic free Ca ([Ca]c) (r50.43, P50.0003), and the resting [Ca ...

We have previously shown that disabling forward-mode Na(+)-Ca(2+) exchange in amacrine cells greatly prolongs the depolarization-induced release of transmitter. To investigate the mechanism for this, we imaged [Ca(2+)](i) in segments of dendrites during depolarization. Removal of [Na(+)](o) produced no immediate effect on resting [Ca(2+)](i) but did prolong [Ca(2+)](i) transients induced by bri...

Zhang, Shen, Jason X.-J. Yuan, Kim E. Barrett, and Hui Dong. Role of Na /Ca exchange in regulating cytosolic Ca in cultured human pulmonary artery smooth muscle cells. Am J Physiol Cell Physiol 288: C245–C252, 2005. First published September 29, 2004; doi:10.1152/ajpcell.00411.2004.—A rise in cytosolic Ca concentration ([Ca ]cyt) in pulmonary artery smooth muscle cells (PASMC) is an important s...

The whole cell patch-clamp technique, in both standard and perforated patch configurations, was used to study the influence of Na+-Ca++ exchange on rundown of voltage-gated Ca++ currents and on the duration of tail currents mediated by Ca++-dependent Cl- channels. Ca++ currents were studied in GH3 pituitary cells; Ca++-dependent Cl- currents were studied in AtT-20 pituitary cells. Na+-Ca++ exch...