2.3. Cardiac perfusion and tissue preparation

Following the exposure period and passive avoidance tests, the rats were anesthetized with ketamine (5 mg/kg i.p.) and Xylazin (2 mg/kg i.p.). Cardiac perfusion was performed with 10% neutral buffered formalin while the heartbeat continued. Following the perfusion, the brain and cerebellum were processed in graded alcohols (70% to 100%) and xylene, and embedded in paraffin for sectioning. Sections of the hippocampus and cerebellum were taken with a rotary microtome (Leica RM 2135; Leica Instruments, Nussloch, Germany). Next, using systematic random sampling, 20 μm thick serial sections were obtained from paraffin-embedded blocks in the sagittal plane. One out of every six sections was selected for analysis, placed on coated slides, and stained with cresyl violet.