Rat pups on PN7, 9, 11 were treated with PCP (10 mg/kg, i.p.) or saline. DHX (3 mg/kg, s.c.) or SCH23390 (1 mg/kg, s.c.) was administered 30 min prior to PCP or saline either alone or in combination. Pups were sacrificed by decapitation 8 hr following the treatment. Tissue from the frontal cortex was dissected and homogenized in ice-cold RIPA buffer containing proteinase inhibitors. A. Representative western blots showing procaspase-3 (∼32 kDa) and the active caspase-3 fragment (17 kDa) from the control and treated rat pups. B. Activated caspase-3 normalized as its ratio to procaspase-3 in the four treatment groups. The quantified WB data are from 4 separate experiments. C. The effect of DHX (with or without pretreatment with SCH23390) on PCP-induced (PN7, 9 and 11) deficits in prepulse inhibition (PPI) of acoustic startle. Following the indicated drug treatment on PN7, 9, 11, PPI of acoustic startle was measured on PN26–28. Values shown are mean ± SEM (** P< 0.01 vs saline or control, ## P< 0.01 vs PCP treatment, $$ P< 0.01 vs DHX+PCP group, one-way ANOVA with Newman-Keuls post hoc test, N = 4 for (B), N= 5–7/group for (C).