Fig. 4

Prevention of colchicine-triggered apoptosis by ATP depletion. (A) CGC were incubated with deoxyglucose (DG, 2 mM), MPP⁺ (50 µM), GSNO (100 µM), or colchicine (1 µM), and cellular ATP was measured after the times indicated. ATP content in control neurons was 2.8 nmol/mg protein, and data are given as percent of untreated control cells. Data are means ± SEM from quadruplicate measurements. (B) Left: CGC were incubated with colchicine (0 or 1 µM) for 24 hr in the continuous presence of DG (2 mM) GSNO (100 µM), MPP⁺ (50 µM), or solvent control DMSO (dimethylsulphoxide) in normal culture medium containing 25 mM potassium. Right: medium was exchanged for a controlled salt solution (27,31) containing 0.5 mM glucose and either 5 or 25 mM potassium. In addition, cells were incubated with 0 or 2 mM DG. The percentage of apoptotic neurons was determined after staining with H-33342. Data are means ± SD from three different experiments.