The effect of hyperbaric oxygen on regional brain and spinal cord levels of nitric oxide metabolites in rat

Hyperbaric oxygen (HBO2) therapy is reported to be beneficial in transient brain ischemia. The present study was conducted to determine the influence of HBO2 on metabolites of nitric oxide (NO) in brain and spinal cord of rats. Rats were exposed to room air (RA), normobaric air (NBA), normobaric oxygen (NBO2), hyperbaric air (HBA) or HBO2, the last two conditions at 2.5 ATA (atmosphere absolute) for 60 min. The results demonstrate that, compared to the NBA control, oxygen alone generally reduced tissue levels of NOx− (nitrite plus nitrate). On the other hand, 2.5 ATA alone tended to have a slight, if any, effect on tissue levels of NOx−. The combination of oxygen and pressure (i.e., HBO2) generally led to an increase in tissue levels of NOx−. Based on these findings, it is concluded that HBO2 appears to markedly increase NO function most notably in the corpus striatum, brainstem, cerebellum and spinal cord.