Carbachol-induced dispersion requires intracellular, but not extracellular, Ca2+ sources. Isolated RPE cells were first treated with 10 μM forskolin for 45' to induce aggregation. Following aggregation, cells were treated with 100 nM carbachol (Carb) along with verapamil (Ver), BAPTA-AM (BAPTA) or DMSO as a carrier control for BAPTA-AM. The mean pigment index of cells treated with BAPTA-AM was significantly different than the mean pigment index of cells treated with carbachol alone. Dispersion was inhibited 95% in cells treated with 1 μM BAPTA and 82% in those treated with 30 μM BAPTA. No statistically significant differences were found between the FSK, BAPTA at 1 μM, or BAPTA at 30 μM treatments. As for verapamil-treated cells, no inhibition of dispersion was observed, nor was dispersion inhibited in DMSO controls. In addition, 100 nM carbachol was applied to cells in either Ringer or in Ca2+-free Ringer. The mean pigment index of the Ca2+-free treatment was not different statistically from the carbachol control. The error bars represent the standard error of the mean (SEM).
Johnson and García BMC Cell Biology 2007 8:53 doi:10.1186/1471-2121-8-53