This issue of The Journal includes an important pair of articles (Albrecht et al. 2001; Hongpaisan et al. 2001) that provide a comprehensive analysis of ER contributions to the handling of depolarization-induced Ca2+ loads in bullfrog sympathetic ganglion neurons. The articles include measurements of ER total [Ca] made within individual cisternae identified in cryosections from rapidly frozen cells, using energy-dispersive X-ray microanalysis. Use of the perforated patch recording technique (which avoids the cytosolic dialysis produced by whole-cell recording) allowed an impressive degree of stability in the voltage-clamped currents and fura-2–based measurements of cytosolic [Ca2+] (see Fig. 1 of Albrecht et al. 2001).
Measurements of ER total [Ca] are more direct than the conventional approach of inferring changes in ER [Ca] by measuring how various ER-modifying drugs influence cytosolic [Ca2+]...
