Abstract
1. Twitch shortening of isolated rat ventricular myocytes was measured on exposure to complete metabolic blockade (2 mM-cyanide in the presence of 10 mM-2-deoxyglucose). Under these conditions twitch shortening declines to undetectable levels over 1-15 min. This 'early' contractile failure is followed by the development of a maintained contracture. 2. Contractures induced by caffeine (20 mM) were similar in amplitude before and after 'early' contractile failure. This result suggests that 'early' contractile failure is not due to depletion of Ca2+ from the sarcoplasmic reticulum. 3. The action potential shortened as the twitch magnitude declined during 'early' contractile failure, raising the possibility of a causal link. Voltage-clamp experiments show that an enormous increase in K+ conductance (greater than 20-fold) occurs during the period of 'early' contractile failure, and presumably underlies the action potential shortening. 4. If the K+ conductance changes are inhibited by replacement of intracellular K+ with N-methyl glucosamine and inclusion of 2 mM-tolbutamide in intra- and extracellular solutions, good voltage control can be achieved. Under these conditions, 'early' contractile failure did not occur on exposure to complete metabolic blockade and neither Ca2+ current nor the twitch were completely abolished until a maintained contracture had begun to occur. 5. Injection of ATP following 'early' contractile failure could partially restore the twitch and prolong the foreshortened action potential. 6. These results are consistent with the hypothesis that 'early' contractile failure occurring under non-voltage-clamped conditions is due principally to failure of activation of the Ca2+ current because of the shortening of the action potential. Although a decline in the availability of Ca2+ current also occurs, action potential shortening results mainly from increased conductance through ATP-sensitive K+ channels which are activated by a fall of intracellular [ATP]. Contractile failure arises not because of a primary alteration, or defect, in the coupling of excitation to contraction, but because the cell membrane is effectively clamped at a potential close to the K+ equilibrium potential.
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Selected References
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- Allen D. G., Morris P. G., Orchard C. H., Pirolo J. S. A nuclear magnetic resonance study of metabolism in the ferret heart during hypoxia and inhibition of glycolysis. J Physiol. 1985 Apr;361:185–204. doi: 10.1113/jphysiol.1985.sp015640. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Allen D. G., Orchard C. H. Intracellular calcium concentration during hypoxia and metabolic inhibition in mammalian ventricular muscle. J Physiol. 1983 Jun;339:107–122. doi: 10.1113/jphysiol.1983.sp014706. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Allen D. G., Orchard C. H. Myocardial contractile function during ischemia and hypoxia. Circ Res. 1987 Feb;60(2):153–168. doi: 10.1161/01.res.60.2.153. [DOI] [PubMed] [Google Scholar]
- Cannell M. B., Lederer W. J. A novel experimental chamber for single-cell voltage-clamp and patch-clamp applications with low electrical noise and excellent temperature and flow control. Pflugers Arch. 1986 May;406(5):536–539. doi: 10.1007/BF00583378. [DOI] [PubMed] [Google Scholar]
- Carmeliet E. Cardiac transmembrane potentials and metabolism. Circ Res. 1978 May;42(5):577–587. doi: 10.1161/01.res.42.5.577. [DOI] [PubMed] [Google Scholar]
- Castle N. A., Haylett D. G. Effect of channel blockers on potassium efflux from metabolically exhausted frog skeletal muscle. J Physiol. 1987 Feb;383:31–43. doi: 10.1113/jphysiol.1987.sp016394. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chapman R. A., Léoty C. The time-dependent and dose-dependent effects of caffeine on the contraction of the ferret heart. J Physiol. 1976 Apr;256(2):287–314. doi: 10.1113/jphysiol.1976.sp011326. [DOI] [PMC free article] [PubMed] [Google Scholar]
- DE MELLO W. C. Metabolism and electrical activity of the heart: action of 2-4-dinitrophenol and ATP. Am J Physiol. 1959 Feb;196(2):377–380. doi: 10.1152/ajplegacy.1959.196.2.377. [DOI] [PubMed] [Google Scholar]
- Eisner D. A., Elliott A. C., Smith G. L. The contribution of intracellular acidosis to the decline of developed pressure in ferret hearts exposed to cyanide. J Physiol. 1987 Oct;391:99–108. doi: 10.1113/jphysiol.1987.sp016728. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fabiato A., Fabiato F. Effects of magnesium on contractile activation of skinned cardiac cells. J Physiol. 1975 Aug;249(3):497–517. doi: 10.1113/jphysiol.1975.sp011027. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fabiato A., Fabiato F. Effects of pH on the myofilaments and the sarcoplasmic reticulum of skinned cells from cardiace and skeletal muscles. J Physiol. 1978 Mar;276:233–255. doi: 10.1113/jphysiol.1978.sp012231. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goldman Y. E., Hibberd M. G., Trentham D. R. Initiation of active contraction by photogeneration of adenosine-5'-triphosphate in rabbit psoas muscle fibres. J Physiol. 1984 Sep;354:605–624. doi: 10.1113/jphysiol.1984.sp015395. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hamill O. P., Marty A., Neher E., Sakmann B., Sigworth F. J. Improved patch-clamp techniques for high-resolution current recording from cells and cell-free membrane patches. Pflugers Arch. 1981 Aug;391(2):85–100. doi: 10.1007/BF00656997. [DOI] [PubMed] [Google Scholar]
- Irisawa H., Kokubun S. Modulation by intracellular ATP and cyclic AMP of the slow inward current in isolated single ventricular cells of the guinea-pig. J Physiol. 1983 May;338:321–337. doi: 10.1113/jphysiol.1983.sp014675. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Isenberg G., Vereecke J., van der Heyden G., Carmeliet E. The shortening of the action potential by DNP in guinea-pig ventricular myocytes is mediated by an increase of a time-independent K conductance. Pflugers Arch. 1983 Jun 1;397(4):251–259. doi: 10.1007/BF00580257. [DOI] [PubMed] [Google Scholar]
- Kakei M., Noma A., Shibasaki T. Properties of adenosine-triphosphate-regulated potassium channels in guinea-pig ventricular cells. J Physiol. 1985 Jun;363:441–462. doi: 10.1113/jphysiol.1985.sp015721. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kammermeier H., Schmidt P., Jüngling E. Free energy change of ATP-hydrolysis: a causal factor of early hypoxic failure of the myocardium? J Mol Cell Cardiol. 1982 May;14(5):267–277. doi: 10.1016/0022-2828(82)90205-x. [DOI] [PubMed] [Google Scholar]
- Kentish J. C. The effects of inorganic phosphate and creatine phosphate on force production in skinned muscles from rat ventricle. J Physiol. 1986 Jan;370:585–604. doi: 10.1113/jphysiol.1986.sp015952. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kohlhardt M., Kübler M. The influence of metabolic inhibitors upon the transmembrane slow inward current in the mammalian ventricular myocardium. Naunyn Schmiedebergs Arch Pharmacol. 1975;290(2-3):265–274. doi: 10.1007/BF00510555. [DOI] [PubMed] [Google Scholar]
- Nayler W. G., Poole-Wilson P. A., Williams A. Hypoxia and calcium. J Mol Cell Cardiol. 1979 Jul;11(7):683–706. doi: 10.1016/0022-2828(79)90381-x. [DOI] [PubMed] [Google Scholar]
- Nilius B., Hess P., Lansman J. B., Tsien R. W. A novel type of cardiac calcium channel in ventricular cells. Nature. 1985 Aug 1;316(6027):443–446. doi: 10.1038/316443a0. [DOI] [PubMed] [Google Scholar]
- Noma A. ATP-regulated K+ channels in cardiac muscle. Nature. 1983 Sep 8;305(5930):147–148. doi: 10.1038/305147a0. [DOI] [PubMed] [Google Scholar]
- Noma A., Shibasaki T. Membrane current through adenosine-triphosphate-regulated potassium channels in guinea-pig ventricular cells. J Physiol. 1985 Jun;363:463–480. doi: 10.1113/jphysiol.1985.sp015722. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schneider J. A., Sperelakis N. The demonstration of energy dependence of the isoproterenol-induced transcellular Ca2+ current in isolated perfused guinea pig hearts--an explanation for mechanical failure of ischemic myocardium. J Surg Res. 1974 Apr;16(4):389–403. doi: 10.1016/0022-4804(74)90060-2. [DOI] [PubMed] [Google Scholar]
- Schuurmans Stekhoven F., Bonting S. L. Transport adenosine triphosphatases: properties and functions. Physiol Rev. 1981 Jan;61(1):1–76. doi: 10.1152/physrev.1981.61.1.1. [DOI] [PubMed] [Google Scholar]
- Stern M. D., Silverman H. S., Houser S. R., Josephson R. A., Capogrossi M. C., Nichols C. G., Lederer W. J., Lakatta E. G. Anoxic contractile failure in rat heart myocytes is caused by failure of intracellular calcium release due to alteration of the action potential. Proc Natl Acad Sci U S A. 1988 Sep;85(18):6954–6958. doi: 10.1073/pnas.85.18.6954. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Taniguchi J., Noma A., Irisawa H. Modification of the cardiac action potential by intracellular injection of adenosine triphosphate and related substances in guinea pig single ventricular cells. Circ Res. 1983 Aug;53(2):131–139. doi: 10.1161/01.res.53.2.131. [DOI] [PubMed] [Google Scholar]
- Van der Heyden G., Vereecke J., Carmeliet E. The effect of cyanide on the K-current in guinea-pig ventricular myocytes. Basic Res Cardiol. 1985;80 (Suppl 1):93–96. doi: 10.1007/978-3-662-11041-6_18. [DOI] [PubMed] [Google Scholar]
