Activation of a capacitative Ca2+ entry pathway by store depletion in cultured hippocampal neurones

Intracellular Ca2+ ([Ca2+](i)) changes were measured in cell bodies of cultured rat hippocampal neurones with the fluorescent indicator Fluo-3. In the absence of external Ca2+, the cholinergic agonist carbachol (200 mu M) and the sarco-endoplasmic reticulum Ca2+ pump inhibitor thapsigargin (0.4 mu M) both transiently elevated [Ca2+](i). A subsequent addition of Ca2+ into the bathing medium caused a second [Ca2+](i) change which was blocked by lanthanum (50 ELM) Taken together, these experiments indicate that stores depletion can activate a capacitative Ca2+ entry pathway in cultured hippocampal neurones and further demonstrate the existence of such a Ca2+ entry in excitable cells. (C) 2000 Federation of European Biochemical Societies.