Fig. 4: Increased TSPO levels following neuronal activation under physiological and psychopharmacological conditions in adult mice.

a Schematic illustration of the experimental design used to assess TSPO levels after neuronal activation under physiological conditions. Mice were exposed to a novel environment (NovE) for 15 min. Gene expression was then assessed 90 min after NovE exposure, whereas protein expression was assessed 180 min post-exposure. Control mice were kept in their familiar home cage (HC) environment. b mRNA levels of cFos, Arc, Zif268 and TSPO (as measured by quantitative polymerase chain reaction) in the hippocampus 90 min after NovE exposure, relative to mice kept in the HC environment. c Intensity (relative optical density) of TSPO protein co-localizing with NeuN-positive neurons (left), Iba1-positive microglia (middle) and GFAP-positive astrocytes in the Hpc 180 min after NovE exposure, relative to mice kept in the HC. The photomicrographs show representative images acquired through confocal microscopy, with nuclear staining (DAPI) in blue, TSPO in green and cell types of interest (neurons, microglia and astrocytes) in red. TSPO co-localizing with the cellular markers of interest appears in yellow. d Schematic illustration of the experimental design used to assess TSPO expression after neuronal activation under psychopharmacological conditions. Mice were injected with saline (Sal) or amphetamine (Amph, 2.5 mg/kg, i.p.) and then placed into an open field to verify Amph-induced hyperlocomotion. Gene expression was evaluated in the nucleus accumbens (NAc) and ventral midbrain (vMB) 90 min after Sal or Amph administration. e Distances moved after Sal or Amph administration as a function of 5-min bins. ***P < 0.001, based on repeated-measures ANOVA. f mRNA levels of cFos and TSPO (as measured by quantitative polymerase chain reaction) in the NAc and vMB 90 min after administration of Sal or Amph. *P < 0.05, **P < 0.01 and ***P < 0.001, based on two-tailed Student’s t-test; each dot in the scatter plot represents an individual animal.