ALTERED [CA2-FACTOR DEPRIVATION(] HOMEOSTASIS IN PC12 CELLS AFTER NERVE GROWTH)

[Ca2+](i) homeostasis in individual PC12, cells after elevated [K+](o) was studied by ratiometric microscopy, during nerve growth factor (NG F) deprivation. A significantly lower number of cells responded with a n increased [Ca2+](i) in the NGF deprived condition. Moreover, the res ponding cells were more deficient in regulating their [Ca2+](i) back t o control levels, after the transient peak. This suggests that differe ntiated neurons do not traverse the apoptotic program homogeneously wi th regard to their [Ca2+](i) regulation and that NGF deprived PC12 cel ls have more difficulties to reduce their [Ca2+](i) after influx of [C a2+](o). (C) 1998 Elsevier Science B.V.