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Elemental composition of Na pump inhibited rabbit aorta VSM cells by electron probe X-ray microanalysis

Publication ,  Journal Article
Krep, H; Lefurgey, A; Graves, SW; Hockett, D; Ingram, P; Hollenberg, NK
Published in: American Journal of Physiology
December 1, 1996

The Na pump in vascular smooth muscle (VSM) is likely to influence not only intracellular Na content but also the content and distribution of other cations and anions measured by electron probe X-ray microanalysis (EPXMA). The hypothesis we tested was that EPXMA of pump-inhibited VSM would yield a characteristic cellular elemental profile, providing insight into the contribution of the Na pump to the intracellular milieu and an approach to identifying when VSM operates under the constraints of pump inhibition. We assessed the contractile state and elemental EPXMA profile of rabbit aorta that was either quiescent or contracted by serotonin (10~6 M) or ouabain (10~6 M). VSM cytoplasm showed the anticipated low Na (28 ±2 mM) and high K (182 ±5 mM) content. With ouabain, Na rose and K fell to reverse the Na-to-Kratio (0.15 ±0.01 vs. 6.6 ±0.3; P < 0.01). With serotonin, the ratio rose slightly (0.28 ±0.2; P < 0.05). Nuclei and mitochondria showed a similar pattern. Cl showed a small increase (56 ±2 to 102 ±4 mM) with ouabain, a shift that could not be accounted for on the basis of charge redistribution to maintain neutrality because the change in Na and K were essentially offsetting. EPXMA measures total and not ionized Ca. If changes in cytoplasmic Ca occurred, they were too small to be measured by the imaging methods employed. The sustained, myogenic contractile response of VSM to Na pump inhibition shows a characteristic elemental profile that could prove useful in its identification. Direct measurement of membrane potential during the myogenic response to Na pump inhibition should have a high priority.

Duke Scholars

Published In

American Journal of Physiology

ISSN

0002-9513

Publication Date

December 1, 1996

Volume

271

Issue

2 PART 2

Related Subject Headings

  • Cardiovascular System & Hematology
 

Citation

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Krep, H., Lefurgey, A., Graves, S. W., Hockett, D., Ingram, P., & Hollenberg, N. K. (1996). Elemental composition of Na pump inhibited rabbit aorta VSM cells by electron probe X-ray microanalysis. American Journal of Physiology, 271(2 PART 2).
Krep, H., A. Lefurgey, S. W. Graves, D. Hockett, P. Ingram, and N. K. Hollenberg. “Elemental composition of Na pump inhibited rabbit aorta VSM cells by electron probe X-ray microanalysis.” American Journal of Physiology 271, no. 2 PART 2 (December 1, 1996).
Krep H, Lefurgey A, Graves SW, Hockett D, Ingram P, Hollenberg NK. Elemental composition of Na pump inhibited rabbit aorta VSM cells by electron probe X-ray microanalysis. American Journal of Physiology. 1996 Dec 1;271(2 PART 2).
Krep, H., et al. “Elemental composition of Na pump inhibited rabbit aorta VSM cells by electron probe X-ray microanalysis.” American Journal of Physiology, vol. 271, no. 2 PART 2, Dec. 1996.
Krep H, Lefurgey A, Graves SW, Hockett D, Ingram P, Hollenberg NK. Elemental composition of Na pump inhibited rabbit aorta VSM cells by electron probe X-ray microanalysis. American Journal of Physiology. 1996 Dec 1;271(2 PART 2).

Published In

American Journal of Physiology

ISSN

0002-9513

Publication Date

December 1, 1996

Volume

271

Issue

2 PART 2

Related Subject Headings

  • Cardiovascular System & Hematology