Biophysical Journal 65: 196-204 (1993)
© 1993 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by White, R L Articles by Wittenberg, B A Search for Related Content PubMed PubMed Citation Articles by White, R L Articles by Wittenberg, B A

NADH fluorescence of isolated ventricular myocytes: effects of pacing, myoglobin, and oxygen supply.

Department of Physiology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140.

ABSTRACT

Endogenous fluorescence was used to measure the extent of reduction of mitochondrial NAD in individual, isolated rat cardiac myocytes. NAD reduction was determined from emitted fluorescence at 415 and 470 nm during brief epi-illumination at 365 nm. NAD reduction of resting myocytes, superfused with medium equilibrated with 95% O2/5% CO2, was 27 +/- 3% (SE) (n = 78), comparable to that in beating whole heart. Increasing intracellular Ca2+ did not significantly change NAD reduction. NAD reduction decreased reversibly to 11 +/- 1% (n = 78) in contracting myocytes electrically paced at 5 Hz for 10 min. Oxygen uptake was stimulated fivefold. There was minimal change in sarcoplasmic pH measured by fluorescence of carboxy-seminaphthorhodafluor-1. However, NAD reduction increased reversibly in response to electrically paced contractions when: (a) myoglobin was inactivated with sodium nitrite (37 +/- 7%; n = 48); or (b) cells were more densely layered and gassed with 20% O2/5% CO2 (48 +/- 3%; n = 30). We conclude that (a) the ratio NADH/NAD is decreased in well-oxygenated cells with increased work; (b) steady-state NAD reduction is increased with increased work when oxygen delivery is limited; and (c) functional myoglobin ensures an oxygen supply to the mitochondria of working cells.

This article has been cited by other articles:

				E. Takahashi, T. Takano, Y. Nomura, S. Okano, O. Nakajima, and M. Sato In vivo oxygen imaging using green fluorescent protein Am J Physiol Cell Physiol, October 1, 2006; 291(4): C781 - C787. [Abstract] [Full Text] [PDF]

				C. J. Bell, N. A. Bright, G. A. Rutter, and E. J. Griffiths ATP Regulation in Adult Rat Cardiomyocytes: TIME-RESOLVED DECODING OF RAPID MITOCHONDRIAL CALCIUM SPIKING IMAGED WITH TARGETED PHOTOPROTEINS J. Biol. Chem., September 22, 2006; 281(38): 28058 - 28067. [Abstract] [Full Text] [PDF]

				M. C. Hogan, C. M. Stary, R. S. Balaban, and C. A. Combs NAD(P)H fluorescence imaging of mitochondrial metabolism in contracting Xenopus skeletal muscle fibers: effect of oxygen availability J Appl Physiol, April 1, 2005; 98(4): 1420 - 1426. [Abstract] [Full Text] [PDF]

				N. Sharma, I. C. Okere, D. Z. Brunengraber, T. A. McElfresh, K. L. King, J. P. Sterk, H. Huang, M. P. Chandler, and W. C. Stanley Regulation of pyruvate dehydrogenase activity and citric acid cycle intermediates during high cardiac power generation J. Physiol., January 15, 2005; 562(2): 593 - 603. [Abstract] [Full Text] [PDF]

				E. Takahashi and K. Asano Mitochondrial respiratory control can compensate for intracellular O2 gradients in cardiomyocytes at low PO2 Am J Physiol Heart Circ Physiol, September 1, 2002; 283(3): H871 - H878. [Abstract] [Full Text] [PDF]

				Y. G. Wang, W. J. Benedict, J. Huser, A. M. Samarel, L. A. Blatter, and S. L. Lipsius Brief rapid pacing depresses contractile function via Ca2+/PKC-dependent signaling in cat ventricular myocytes Am J Physiol Heart Circ Physiol, January 1, 2001; 280(1): H90 - H98. [Abstract] [Full Text] [PDF]

				R. L. White and B. A. Wittenberg Mitochondrial NAD(P)H, ADP, oxidative phosphorylation, and contraction in isolated heart cells Am J Physiol Heart Circ Physiol, October 1, 2000; 279(4): H1849 - H1857. [Abstract] [Full Text] [PDF]

				C.-j. Liu, H. Wang, Z. Zhao, S. Yu, Y.-b. Lu, J. Meyer, G. Chatterjee, S. Deschamps, B. A. Roe, and P. Lengyel MyoD-Dependent Induction during Myoblast Differentiation of p204, a Protein Also Inducible by Interferon Mol. Cell. Biol., September 15, 2000; 20(18): 7024 - 7036. [Abstract] [Full Text]

				C. Gibbs Respiratory control in normal and hypertrophic hearts Cardiovasc Res, June 1, 1999; 42(3): 567 - 570. [Full Text] [PDF]

				E. Takahashi, H. Endoh, and K. Doi Intracellular gradients of O2 supply to mitochondria in actively respiring single cardiomyocyte of rats Am J Physiol Heart Circ Physiol, February 1, 1999; 276(2): H718 - H724. [Abstract] [Full Text] [PDF]

				R. Brandes, L. S. Maier, and D. M. Bers Regulation of Mitochondrial [NADH] by Cytosolic [Ca2+] and Work in Trabeculae From Hypertrophic and Normal Rat Hearts Circ. Res., June 15, 1998; 82(11): 1189 - 1198. [Abstract] [Full Text] [PDF]