|
|
||||||||
AJP - Cell Physiology, Vol 266, Issue 1 C311-C317, Copyright © 1994 by American Physiological Society
ARTICLES |
M. L. Borin, R. M. Tribe and M. P. Blaustein
Department of Physiology, School of Medicine, University of Maryland, Baltimore 21201.
The effect of a rise in intracellular Na+ concentration ([Na+]cyt) on the amount of Ca2+ in intracellular stores was studied in vascular smooth muscle cells from the A7r5 line. The relative amount of stored Ca2+ was estimated in fura 2-loaded cells by the rise in cytosolic free Ca2+ concentration ([Ca2+]cyt) evoked by Ca2+ release from the sarcoplasmic reticulum (SR). To improve the detection of released Ca2+, extrusion of Ca2+ from the cytosol was minimized by using nominally Na+/Ca(2+)-free medium containing 0.5 mM La3+ [for vasoconstrictor experiments, the medium contained 0.5 mM ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid and no La3+]. Ca2+ release was triggered by thapsigargin (TG), an SR Ca(2+)-ATPase inhibitor, and by the vasoconstrictors arginine vasopressin (AVP) and serotonin (5-HT). Incubation with 1-3 mM ouabain for 20 min, which raises [Na+]cyt from 4.4 to 9.0 mM, increased "resting" [Ca2+]cyt only slightly (from 87 to 122 nM). However, ouabain greatly augmented the release of Ca2+ evoked by TG [from 639 nM (control) to 1,021 nM], by AVP (from 993 to 1,597 nM), and by 5-HT (from 559 to 1,486 nM). Ouabain-induced augmentation of TG-evoked Ca2+ release was not affected by 10 microM verapamil; this implies that the effect of ouabain was not due to Ca2+ entry through voltage-gated Ca2+ channels. The response to TG was not augmented when ouabain was applied for 20 min in Na(+)-free medium (Na+ replaced by equimolar N-methyl-D-glucamine) to prevent [Na+]cyt from rising.(ABSTRACT TRUNCATED AT 250 WORDS)
This article has been cited by other articles:
![]() |
S. Zhang, H. Dong, L. J. Rubin, and J. X.-J. Yuan Upregulation of Na+/Ca2+ exchanger contributes to the enhanced Ca2+ entry in pulmonary artery smooth muscle cells from patients with idiopathic pulmonary arterial hypertension Am J Physiol Cell Physiol, June 1, 2007; 292(6): C2297 - C2305. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. Liu, J. Abramowitz, A. Askari, and J. C. Allen Role of caveolae in ouabain-induced proliferation of cultured vascular smooth muscle cells of the synthetic phenotype Am J Physiol Heart Circ Physiol, November 1, 2004; 287(5): H2173 - H2182. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. F. Ethier, H. Yamaguchi, and J. M. Madison Effects of cyclopiazonic acid on cytosolic calcium in bovine airway smooth muscle cells Am J Physiol Lung Cell Mol Physiol, July 1, 2001; 281(1): L126 - L133. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Wu and C. H. Fry Na+/Ca2+ exchange and its role in intracellular Ca2+ regulation in guinea pig detrusor smooth muscle Am J Physiol Cell Physiol, May 1, 2001; 280(5): C1090 - C1096. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Kostrzewska, B. Modzelewska, and S. Batra Source of calcium for contractile responses of large and small human intramyometrial arteries Hum. Reprod., September 1, 2000; 15(9): 1927 - 1931. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. P. Blaustein and W. J. Lederer Sodium/Calcium Exchange: Its Physiological Implications Physiol Rev, July 1, 1999; 79(3): 763 - 854. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. K. Slodzinski and M. P. Blaustein Physiological effects of Na+/Ca2+ exchanger knockdown by antisense oligodeoxynucleotides in arterial myocytes Am J Physiol Cell Physiol, July 1, 1998; 275(1): C251 - C259. [Abstract] [Full Text] [PDF] |
||||
![]() |
X. Liu, L. J. Hymel, and E. Songu-Mize Role of Na+ and Ca2+ in stretch-induced Na+-K+-ATPase alpha -subunit regulation in aortic smooth muscle cells Am J Physiol Heart Circ Physiol, January 1, 1998; 274(1): H83 - H89. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. Karaki, H. Ozaki, M. Hori, M. Mitsui-Saito, K.-I. Amano, K.-I. Harada, S. Miyamoto, H. Nakazawa, K.-J. Won, and K. Sato Calcium Movements, Distribution, and Functions in Smooth Muscle Pharmacol. Rev., June 1, 1997; 49(2): 157 - 230. [Abstract] [Full Text] [PDF] |
||||
![]() |
J.-R. Nofer, M. Tepel, B. Kehrel, S. Wierwille, M. Walter, U. Seedorf, W. Zidek, and G. Assmann Low-Density Lipoproteins Inhibit the Na+/H+ Antiport in Human Platelets: A Novel Mechanism Enhancing Platelet Activity in Hypercholesterolemia Circulation, March 18, 1997; 95(6): 1370 - 1377. [Abstract] [Full Text] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |