Pv. Belan et al., A NEW TECHNIQUE FOR ASSESSING THE MICROSCOPIC DISTRIBUTION OF CELLULAR CALCIUM EXIT SITES, Pflugers Archiv, 433(1-2), 1996, pp. 200-208
This paper contains a description of a new method designed to monitor
the distribution of Ca2+ efflux from cells or small cellular aggregate
s. The idea behind this method is to use a fluorescent Ca2+ indicator
bound to dextrans of high molecular weight to slow down Ca2+ diffusion
. Due to the decrease in diffusion rate, Ca2+ ions should be held clos
e to the site of their release from the cells for a relatively long ti
me, enough for the confocal microscope to detect such a local increase
in Ca2+ concentration. This paper gives a detailed description of the
method, illustrated with results of measurements of agonist-dependent
and agonist-independent Ca2+ extrusion from pancreatic acinar cells.
An appendix provides the mathematical background that should allow sel
ection of the concentration of buffer which is necessary to achieve a
particular Ca2+ diffusion coefficient.