The focus dependent effects of Z Asp CH DCB on MTT reduction activities and LDH release are shown in 2 Fig. 3. Z Asp CH DCB at 30 mM potently restricted LDH release. The inhibition reached a at 50 mM 2 Z Asp CH buy A66 and was preserved as much as at least 200 mM. In this concentration range, only a small effect was observed 2 in MTT assay. Such dissociation of the result of these caspase inhibitors on MTT reduction activity and LDH release might be seen if these inhibitors wait neuronal cell death, while the decrease in cellular MTT reduction activity precedes release of cellular LDH activity Ref. w15x and Fig. 1B.. Consequently, we examined the consequence of Z Asp CH DCB at 48 h following the low KCl 2 treatment. The results on LDH launch and MTT reduction at 48 h were just like those observed at 2-4 h 48 h after low KCl treatment, MTT reduction action of low KCl, high KCl, low KClq100 mM Z Asp CH DCB samples were 2-3. 4 of whole cells, respectively, LDH activities produced in culture medium of low KCl, large KCl, low KClq100 mM Z Asp CH DCB samples were 16. 1 of total cellular LDH 2 action, data are mean S. D. of four independent experiments.. Three low KCl induced apoptosis was prevented by caspase inhibitors with little effect on cellular MTT reduction activity. We tested Cellular differentiation the consequence of Z Asp CH DCB on cellular reduction activity utilizing the substrates WST 1 and XTT, tetrazolium redox dyes commonly used for measurement of cell viability w32x, to extend these results further. Low KCl therapy for 24 h caused a decrease of cellular reduced amount of WST 1 and XTT as well as MTT, as shown in Dining table 3. While Z Asp CH DCB 30 mM. exerted little influence on MTT reduction exercise, it partially prevented a decrease of WST 1 2 reduction and XTT reduction activities. Similar to the effect of Z Asp CH DCB, the effect of actinomycin D 1 mgrml. 2 to the decrease of WST 1 reduction and XTT reduction activities were also incomplete Dining table 3.. As cellular MTT reduction activity possibly demonstrates cellular metabolic activity w38x, neurons rescued from minimal KCl induced apoptosis Lu AA21004 by several caspase inhibitors are probably in a state. To look at this possibility, we measured ATP degrees of the neurons rescued by these caspase inhibitors. ATP levels were paid down by about 40-oz at 24 h after low KCl therapy Fig. 4.. ATP quantities of the neurons recovered by Z Asp CH DCB 100 mM. and Boc Asp FMK 30 2 mM. are somewhat below that of the KCl treated neurons and similar to that of the low KCl treated neurons. In contrast, neurons recovered by actinomycin D maintained ATP levels similar to those of the KCl treated neurons.