Figure 1: Variations in tolerance to sodium nitroprusside (6 mg/kg, i.p.) as assessed by the percent of mortality at each of the six circadian dosing times (1, 5, 9, 13, 17, and 21 HALO) in a total of 72 Swiss albino male and female mice aged 2 weeks. 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.