Fig. 7.
Delayed calcium deregulation is not caused by Ca2+ entry through defined calcium channels. Granule cells were exposed to 100 μm glutamate–10 μm glycine at t = 2 min. After 50 min, a population of cells had deregulated. Ca2+channel antagonists were added sequentially, where indicated by thedotted lines: (1) 1 μm nifedipine; (2) 5 μmConus magnus toxin-MVIIC; (3) 1 μm6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione; and (4) 1 μm MK-801. The [Ca2+]cresponses of three representative cells are shown: cella had deregulated before addition of the inhibitors, cell b initiated deregulation, and cell crecovered to a lower [Ca2+]c.