Bioluminescence Imaging. Bioluminescence was detected with the In Vivo Imaging System (18) (IVIS; Xenogen, Alameda, CA). Mice were injected i.p. with 150 mg/kg D-luciferin (Xenogen) 10 min before imaging and anesthetized with isoflurane during imaging. Photons emitted from living mice were acquired as photons per s/cm2 per steridian (sr) by using LIVINGIMAGE software (Xenogen) and integrated over 5 min. For photon quantification, a region of interest was manually selected and kept constant within all experiments; the signal intensity was converted into photons per s/cm2 per sr. For longitudinal comparison of bioluminescence, baseline imaging was performed 24 h before KA was administered. Bioluminescence was expressed as fold induction over baseline levels. In addition, a background bioluminescence reading obtained in nontransgenic mice injected with luciferin was subtracted from all values. For brain slice imaging, coronal brain slices (2- to 3-mm thickness) were obtained by cutting brains in a mouse brain matrix (Harvard Apparatus, Holliston, MA). Slices were bathed in tissue culture medium containing luciferin (150 μg/ml) in 24-well plates and imaged immediately.