FIGURE 5.
N2a cells release ATP by a NEM-sensitive mechanism. A, shown are representative records of luminescence evoked by ATP released into the extracellular medium of N2a cells before (Control) and after ionomycin (10 μm) stimulation in the absence (ionomycin) or presence of the ecto-ATPase inhibitor ARL67156 (100 μm; ARL + Iono) or ARL67156 plus the exocytosis inhibitor NEM (500 μm; NEM + ARL + Iono). Extracellular medium was collected after a 5-min exposure of the cells to each of the different experimental conditions. Luminescence is expressed as relative light units (RLU). B, quantification of ATP release under the different experimental conditions is shown. Each bar represents the mean ± S.E. of the results from three experiments. A calibration curve generated with serial dilutions of an ATP standard was used to convert luminescence units into ATP concentration values. **, p < 0.005; ***, p < 0.001 with respect to control; ###, p < 0.001 compared with ARL67156 + ionomycin.