Influence of nitric oxide synthase inhibitor on gerbil behavior after hyperbaric oxygen-induced convulsion

摘要

BACKGROUND:Studies have reported that nitric oxide synthase (NOS) inhibitor can prolong the latency of hyperbaric oxygen-induced convulsion (HBOC). However, there are very few reports addressing the influence of NOS inhibitor on mental behavior. OBJECTIVE: To investigate behavioral changes after HBOC in gerbils, as well as the influence of NOS inhibitor. DESIGN, TIME AND SETTING: Randomized experiments were performed in the Laboratory of Hyperbaric Pressure and Diving Physiology, Naval Medical Research Institute of Chinese PLA (Shanghai, China) from March 2005 to June 2007. MATERIALS: Forty male gerbils were randomly divided into five groups: HBOC, saline control, NOS inhibitor, pressure control, and normal control. Each group contained eight animals. METHODS: In the HBOC group, once depression induction ended, animals were removed from the chamber five minutes after the first appearance of generalized convulsion induced by 0.5 MPa hyperbaric oxygen. Ten minutes before entering the chamber, saline control and NOS inhibitor animals were intraperitoneally injected with 1 mL saline and 20 mg/kg NG-nitro-L-arginine, respectively. The pressure control group was only exposed to 0.5 MPa. The remaining procedures in these three groups were identical to the HBOC group. The normal control group received no intervention. MAIN OUTCOME MEASURES: Open field test scores in gerbils prior to HBOC, as well as immediately, 24 hours, and 72 hours after decompression ended. RESULTS: HBOC was not detected in either the normal control or the pressure control group, and there were no significant differences in open field test scores prior to and after HBOC (P > 0.05). HBOC occurred in the HBOC, saline control, and NOS inhibitor groups, with significant differences in open field test scores after decompression ended compared to normal control and pressure control groups (P < 0.05–0.01). Compared to the HBOC and saline control groups, the NOS inhibitor group exhibited a significantly lower score in the open field test immediately after decompression, and a higher score at 24 and 72 hours (P < 0.05–0.01). CONCLUSION: NOS inhibitor can regulate behavioral changes in gerbils after HBOC.