(A & B) Active caspase-3 ELISA assay. Cortical neurons were prepared from E16 rat embryonic. The neurons were pretreated with different doses of compounds as indicated for 30 min, followed by 50 μM glutamate for 16 h. The cell lysates were analyzed by active caspse-3 ELISA. (C) 4'-DMA-7,8-DHF and 7,8-DHF prevent KA-elicited neuronal cell death. C57BL/6J mice were orally administrated with 5 mg/kg of 4'-DMA-7,8-DHF and 7,8-DHF, at different time points, the mice were i.p. injected with 20 mg/kg KA for 2 h. The brain lysates were analyzed by immunoblotting with anti-p-TrkB, anti-active caspase-3 antibodies, respectively. (D) TrkB activation is indispensable for the neuroprotective effect of 4'-DMA-7,8-DHF. 4'-DMA-7,8-DHF and 7,8-DHF suppressed KA-induced caspase-3 activation in TrkB F616A mutant knockin mice, which can not be blocked by 1NMPP1 (top panel). TrkB F616A was strongly activated by 4'-DMA-7,8-DHF and 7,8-DHF, which was blocked by 1NMPP1 (middle panel).