Figure 2: Variations of mortality according to the circadian stage (1, 5, 9, 13, 17, and 21 HALO) at various doses (4.9, 5.4, and 6 m/kg, i.p.) of sodium nitroprusside in 2 week old male (a) and female (b) mice. Each point represents the mean ± SEM of four independent experiments. The black bar corresponds to the dark period. Maximums of lethality correspond, irrespective to the gender, to drug dosing at 9 and 21 HALO. The ?2 test detected statistically significant differences in mortality rate related both to dosing time (P = 0.0001) and dose (P < 0.0003).