AJP - Heart and Circulatory Physiology, Vol 253, Issue 6 1400-H1408, Copyright © 1987 by American Physiological Society

ARTICLES

Simultaneous measurement of calcium transients and motion in cultured heart cells

G. A. Peeters, V. Hlady, J. H. Bridge and W. H. Barry
Department of Medicine, University of Utah, Salt Lake City 84132.

The fluorescent Ca2+ probe indo-1 is a new intracellular Ca2+ concentration [( Ca2+]i) indicator that may be suitable for measurement of [Ca2+]i transients in intact heart cells. We exposed spontaneously contracting cultured chick embryo ventricular cells (37 degrees C) to the membrane-permeable indo-1-acetoxymethyl ester (indo-1 AM). Indo-1 loading was associated with a decrease in the amplitude of contraction measured with a video motion detector, but contractility returned to control levels during a subsequent 30-min wash. Analysis of emission spectra of dye obtained by digitonin permeabilization of cells loaded in indo-1 AM showed that the active intracellular dye was not pure indo-1 but probably includes partially deesterified molecules. With the use of an inverted X40 objective epifluorescence system, washed cells containing indo-1 were excited at 360 nm, and fluorescence intensity was measured at 410 nm (increases with increasing [Ca2+]) and 480 nm (decreases with increasing [Ca2+]). Calibration of the [Ca2+]i signals, reflected by the ratio of 410 to 480 nm fluorescence, was achieved by use of ethylen-glycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid (EGTA)-Ca2+ buffered solutions containing the nonfluorescent Ca2+ ionophore Bromo-A23187. Average end-diastolic and peak-systolic [Ca2+]i were 328 +/- 32 and 813 +/- 72 nM (means +/- SE, n = 8). The onset of the [Ca2+]i transient preceded motion by 27 +/- 5 ms (means +/- SE, n = 4), but generally resembled the motion signals in contour. These findings indicate that indo-1 may be used to detect [Ca2+]i transients in isolated ventricular cells without causing significant alterations in mechanical performance.

This article has been cited by other articles:

				S.-i. Yasuda, S. Sugiura, H. Yamashita, S. Nishimura, Y. Saeki, S.-i. Momomura, K. Katoh, R. Nagai, and H. Sugi Unloaded shortening increases peak of Ca2+ transients but accelerates their decay in rat single cardiac myocytes Am J Physiol Heart Circ Physiol, July 11, 2003; 285(2): H470 - H475. [Abstract] [Full Text] [PDF]

				K. Ito, Y. Kagaya, T. Ishizuka, N. Ito, N. Ishide, and K. Shirato Diacylglycerol delays pHi overshoot after reperfusion and attenuates contracture in isolated, paced myocytes Am J Physiol Heart Circ Physiol, November 1, 1999; 277(5): H1708 - H1717. [Abstract] [Full Text] [PDF]

				A. Takahashi, P. Camacho, J. D. Lechleiter, and B. Herman Measurement of Intracellular Calcium Physiol Rev, October 1, 1999; 79(4): 1089 - 1125. [Abstract] [Full Text] [PDF]

				K. Brixius, M. Pietsch, S. Hoischen, J. Muller-Ehmsen, and R. H. G. Schwinger Effect of inotropic interventions on contraction and Ca2+ transients in the human heart J Appl Physiol, August 1, 1997; 83(2): 652 - 660. [Abstract] [Full Text] [PDF]

				H. Ikenouchi, K. Kangawa, H. Matsuo, and Y. Hirata Negative Inotropic Effect of Adrenomedullin in Isolated Adult Rabbit Cardiac Ventricular Myocytes Circulation, May 6, 1997; 95(9): 2318 - 2324. [Abstract] [Full Text]