Effect of Magnesium Pre-treatment on the Hippocampal NOS Activity during Long-lasting Intermittent Hypoxia

Abstract: Influence of magnesium pre-treatment during repetitive hypoxia was studied in the hippocampus of rats by histochemical analysis (NADPH-diaphorase staining). NADPH-diaphorase occurs concurrently with NO-synthase that is responsible for NO synthesis. Rat pups were kept together with their mother for 8 hours a day in a hypobaric chamber at a simulated altitude of 7 000 m since the day of birth till the 17 th day. The first group of animals was exposed to the repeated hypoxia; the second group under the same conditions was pre-treated by magnesium before the exposition to the hypoxia. Both groups were compared with intact control animals and intact animals treated with magnesium. The experimental and control animals were the transaortically perfused with 4 % buffered neutral formaldehyde under thiopental anaesthesia at the age of 35 days. Brains were processed for NADPH-d staining. We estimated the density of NADPH-d positive neurons in CA1 and CA3 areas o