Fig. 2.
a and b. Time courses of changes in the expression of GABAA receptor subunit mRNAs in the hippocampus and thalamus (α1, α2, α4, α5, β2, β3, γ2 and δ). (2a: a–b; f–g; k–l, p–q and 2b: a–b; f–g; k–l, p–q) Representative photomicrographs demonstrating the level of GABAA receptor subunit mRNAs in the hippocampus. (2a: c–e; h–j; m–o, r–t and 2b: c–e; h–j; m–o, r–s) Optic densities for mRNA levels were determined by image analysis (see Methods) of film autoradiographs after in situ hybridization. Relative optic densities (ROD) in the granule cell layer (GCL) and pyramidal cell layers are depicted as red lines for ipsilateral side after TBI and as blue lines for contralateral side after TBI. In k the areas of interest examined are indicated in a representative way for the laterodorsal nucleus (LD) and the area combining the posterior thalamic nuclear group (PO), ventroposterolateral (VPL) and ventroposteromedial (VPM) complex (PO/VPM/VPL) (Swanson, 1992) with red circles and the location where the line scans were set are shown with blue arrows for GCL and hippocampal subfields CA1 and CA3 (nomenclature according to Swanson, 1992). Note that mRNA levels for all other subunits except α4 decrease bilaterally at the early time intervals after TBI (6 h and/or 24 h). However, the mRNA levels mainly recover close to control values on both sides within 4 months. Subunit γ2 mRNA level increases 10 days and levels of α4 and α5 4 months after TBI in sector CA1 indicating reflectory adaptation. Scale bar = 250 μm (a–b, f–g. k–l, p–q). Statistical significance: *p < 0.05, **p < 0.01, ***p < 0.001 as compared to controls. Abbreviations: GCL, granule cell layer. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)