1°GCs were pre-treated for 1 h with (+)-PTZ (0.5, 1 or 3 µM) followed by co-incubation for 6 h (A) or 18 h (B) with Hcy (50 µM) and (+)-PTZ (0.5, 1 or 3 µM). The number of TUNEL-positive cells was determined using the ApopTag fluorescein method. Data are expressed as the mean and S.E. of the ratio of dead/dying cells to the total number of cells, n = 10. (*, significantly different from control, p <0.001; **, significantly different from cells treated with 50 µM Hcy, p<0.001).