Vol. 278, Issue 4, H1371-H1382, April 2000
SPECIAL COMMUNICATION
Generation of intracellular pH gradients in single cardiac myocytes
with a microperfusion system
Kenneth W.
Spitzer,
Philip R.
Ershler,
Rita L.
Skolnick, and
Richard D.
Vaughan-Jones
Nora Eccles Harrison Cardiovascular Research and Training
Institute, University of Utah, Salt Lake City, Utah 84112;
and University Laboratory of Physiology, Oxford OX1 3PT, United
Kingdom
This
study describes the use of a microperfusion system to create rapid,
large regional changes in intracellular pH (pHi) within
single ventricular myocytes. The spatial distribution of pHi in single myocytes was measured with
seminaphthorhodafluor-1 fluorescence using confocal imaging. Changes in
pHi were induced by local external application of
NH4Cl, CO2, or sodium propionate. Local
application was achieved by simultaneously directing two parallel
square microstreams, each 275 µm wide, over a single myocyte oriented
perpendicular to the direction of flow. One stream contained the
control solution, and the other contained a weak acid or base.
End-to-end, stable pHi gradients as large as 1 pH unit were
readily created with this technique. This result indicates that pH
within a single cardiac cell may not always be spatially uniform,
particularly when weak acid or base gradients are present, which can
occur, for example, in regional myocardial ischemia. The
microperfusion method should be useful for studying the effects of
localized acidosis on myocyte function, estimating intracellular ion
diffusion rates, and, possibly, inducing regional changes in other
important intracellular ions.
confocal imaging; intracellular acidosis; ventricular myocytes
