Calcium Release and Force Development in Rat Myocardium
It is well known that cardiovascular control mechanisms which adjust cardiac output to the bloodflow required by the organs in the body continuously modulate force of the heartbeat. The balance between the vagal and sympathetic activities dictates the heart rate, and hence through the force-frequency and force-interval relationships the contractile state of the heart. In addition, adrenergic transmitters and hormones control both calcium transport and the sensitivity of the contractile filaments to calcium ions in the myocyte by their modulation of phosphorylation of calcium channels, calcium pumps and troponin-I. Adjustment of the venous tone by the cardiovascular control mechanisms dictates the work put out by the heart through the mechanism described by Starling, that the change of venous and hence end-diastolic pressure which results from activation of the control system leads to a change in stretch of the cardiac sarcomeres and thereby an increase or decrease of the response of the contractile filaments to calcium ions.
KeywordsMuscle Length Sarcomere Length Calcium Transient Terminal Cisterna Intracellular Calcium Transient
Unable to display preview. Download preview PDF.
- 7.Allen DG, Kurihara S. Calcium transients in mammalian ventricular muscle. Eur Heart J 1:5–15 (1980).Google Scholar
- 8.Spurgeon HA, Baartz G, Capogrossi MC, Raffaeli S, Stern M, Lakatta EG. The relationship between the cytosolic Ca2+ transient and cell length during a twitch in single adult cardiac myocytes, in: Biology of Isolated Adult Cardiac Myocytes. Editors: WA Clark, RS Decker, Borg TK. Elsevier Press, New York. pp350–353 (1988).Google Scholar
- 9.Krueger JW. Measurement and interpretation of contraction in isolated cardiac cells. In: Biology of Isolated Adult Cardiac Myocytes. Editors: WA Clark, RS Decker, Borg TK. Elsevier Press, New York, pp 172–186 (1988).Google Scholar
- 11.duBell WH, Philips CM, Houser SR. A technique for measuring cytosolic free Ca2+ with Indo-1 in feline myocytes, in: Biology of Isolated Adult Cardiac Myocytes. Editors: WA Clark, RS Decker and TK Borg. Elsevier Publishing, New York. ppl87–201 (1988).Google Scholar
- 12.Lee H, Mohabir R, Smith N, Franz MR, Clusin WT. Effect of ischemia on calcium dependent fluorescence transients in rabbit hearts containing Indo-1. Circ Res 1988;78:1047–1059.Google Scholar
- 21.Sitsapesan, R., Montgomery, R.A.P., MacLeod, K.T., Williams, A.J. Increased open probability of sheep cardiac sarcoplasmic reticulum calcium release channels induced by low temperatures. Proceedings of the Physiological Society. March 1990. 28p.Google Scholar
- 42.Quagebeur, J.M. Schouten, V.J.A., ter Keurs, H.E.D.J. Mechanical restitution in human myocardium. J Physiol 377:120p (1986).Google Scholar
- 46.Sagawa K, Maughan L, Suga H, Sunagawa K. Energetics of the Heart, In: Cardiac Contraction and the Pressure-Volume Relationship. Oxford University Press, pp 171–231 (1988).Google Scholar
- 47.Gao WD, ter Keurs HEDJ. Determinants of ATP depletion during metabolic inhibition of rat cardiac muscle. Canadian Cardiovascular Society Meeting (abstract) 1991.Google Scholar
- 48.Banijamali HS, Gao WD, MacIntosh BR, ter Keurs HEDJ. The force-interval relationships of twitches and cold contractures in rat cardiac trabeculae: the effect of ryanodine. Circ Res (in press) 1991.Google Scholar