Using histochemical analysis, the NADPH-diaphorase, Fluoro-Jade B and bis-benzimide (Hoechst 33342) the effect of intraperitoneal administration of pentylentetrazol (PTZ) on hippocampal neurons was studied. 18-day-old male rats of the Wistar strain received PTZ (60 mg/kg) in one dose. The next day, the 19-day-old animals were transcardially perfused with 4% paraformaldehyde under deep thiopental anaesthesia. Cryostat sections were stained to identify NADPH-diaphorase positive neurons that were then quantified in the CA1 and CA3 areas of the hippocampus, in the dorsal and ventral blades of the dentate gyrus and in the hilus of the dentate gyrus. Combination of the Fluoro-Jade B and bis-benzimide (Hoechst 33342) staining was used in the same areas, to identify possible neurodegeneration. Number of NADPH-d positive neurons was higher after pentylentetrazol administration in CA1 and CA3 areas of the hippocampus and in the hilus of the dentate gyrus, compared to the control group which we consider as baseline. Morphological alterations (cell loss) in CA3 area of the hippocampus and in the hilus of the dentate gyrus only (evaluated by Hoechst 33342) were found in animals receiving PTZ; no FJ-B positive cells were found and we can conclude that neurons were destroyed by the PTZ insult.

Institute of Physiology of the 1st Faculty of Medicine Charles University Prague Czech Republic