Cytosolic calcium in the ischemic rabbit heart: assessment by pH- and temperature-adjusted rhod-2 spectrofluorometry

Cytosolic calcium in the ischemic rabbit heart: assessment by pH- and temperature-adjusted rhod-2 spectrofluorometry.

OBJECTIVES Cytosolic calcium ([Ca(2+)](i)) mediates ischemia-reperfusion (I/R) injury, but magnitude and time course of I/R-induced [Ca(2+)](i) overload remain unclear. Fluorescent indicators are commonly used to measure [Ca(2+)](i), and have a dissociation constant (K(d)) that depends on pH and temperature. We hypothesized that changes of K(d) during I/R lead to misleading interpretations of [...

Fluorescence measurement of calcium transients in perfused rabbit heart using rhod 2.

Surface fluorescence spectroscopy of the beating heart to measure cytosolic calcium has been limited by the need to use ultraviolet excitation light for many of the commonly used calcium indicators. Ultraviolet light in the heart produces a high level of background fluorescence and is highly absorbed, limiting tissue penetration. Visible wavelength fluorescence dyes such as rhod 2 are available...

pH-adjusted ionized calcium

Cytosolic free calcium spiking affected by intracellular pH change.

The characteristics underlying cytosolic free calcium oscillation were evaluated by superfused dual wave-length microspectrofluorometry of fura-2-loaded single acinar cells from rat pancreas. Application of a physiological concentration of cholecystokinin octapeptide (CCK) (20 pM) induced a small basal increase in cytosolic free calcium concentration ([Ca2+]i) averaging 34 nM above the prestimu...

Actual ionized calcium (at actual pH) vs adjusted ionized calcium (at pH 7.4) in hemodialyzed patients.

typed double-spaced (including references) with conventional margins. The overall length is limited to five manuscript pages, including not more than one figure or one table. To the Editor: Ionized calcium is now the measurement of choice for evaluating calcium metabolic diseases (1, 2). Ionized calcium may be reported either as the actual ionized calcium, referred to the actual pH of the patie...