Antisense inhibition of na+-ca2+ exchange in primary cultured arterial myocytes. Slodzinski, Martin K., Magdalena Juhaszova, and Mordecai P. Blaustein. Departments of Physiology and Medicine, and the Center for Vascular Biology and Hypertension, University of Maryland School of Medicine, Baltimore, MD 21201
APStracts 2:0292C, 1995.
Slodzinski, M.K., M. Juhaszova and M.P. Blaustein. Antisense Inhibition of Na+-Ca2+ Exchange in Primary Cultured Arterial Myocytes. Am. J. Physiol. 000 (Cell Physiol. 00):C000-C000, 1995. - The effects of chimeric phosphorothioated antisense oligodeoxynucleotides (AS-oligos) targeted against the Na+-Ca2+ exchanger (NCX) were tested in primary cultured rat mesenteric artery myocytes. In parallel cultures, myocytes proliferated, and were morphologically normal, in the presence of scrambled (nonsense, NS-) oligos, antisense (AS-) oligos, or no oligos (controls). NCX function was examined with digital imaging, using Fura-2 to estimate the cytosolic free Ca2+ concentration, [Ca2+]cyt. Resting [Ca2+]cyt was higher (145 +/- 4 nM; P&LT0.05) in AS-oligo treated cells than in controls (125 +/- 5 nM) or NS-oligo treated cells (131 +/- 4 nM). Lowering external Na+, to promote Ca2+ entry via NCX, increased [Ca2+]cyt transiently in controls and NS-oligo treated cells, but not in AS-oligo treated cells. Raising [Na+]cyt with ouabain augmented the low Na+-induced rise in [Ca2+]cyt in controls and NS-oligo treated cells, but AS-oligo treated cells still did not respond. Nevertheless, serotonin (5-HT) increased [Ca2+]cyt in all three groups. Thus, AS-oligos selectively blocked NCX activity, but not the 5-HT response. To determine the effect of NCX knockdown on the modulation of stored Ca2+, the 5-HT response was tested immediately after removal of external Ca2+. Ouabain augmented the 5-HT induced rise in [Ca2+]cyt in control and NS-oligo treated cells, but not AS -oligo treated cells. This indicates that the NCX can modulate intracellular Ca2+ stores. We conclude that AS-oligos are useful for investigating the physiological role of NCX in vascular smooth muscle. 

Received 19 June 1995; accepted in final form 2 August 1995.
APS Manuscript Number C352-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 14 August 1995.