Wake-promoting Actions Of Median Nerve Stimulation In Tbi-coma:A Mechanical Study Of Orexina And Orexin Receptor 1 In Hypothalamic Area

Objective: To investigate the wake-promoting action and potential mechanisms of MNS in TBI-induced coma rats.Method: One hundred-twenty rats were divided into four groups: control, model(TBI), stimulated(TBI+MNS) and antagonist group(TBI+MNS+OX1R antagonist SB334867). We applied MNS to rats after TBI-induced coma model were established.Then, we observed behaviors of rats while MNS was finished and then each ten rats of every group were executed at 6, 12, 24 hour after therapy and observation. The hypothalamic tissues of each rat was separated and extracted. Expression of orexin-A and OX1 R in hypothalamus was examined via immunohistochemistry, westernblotting and ELISA.Result: Twenty-one rats exhibited righting reflex in simulated group. There were seven and ninty rats re-awaked in model and antagonist group, respectively. Amount of orexin-A and OX1 R in each group was compared with others, we found that orexin-A showed an statistically increasing trend in control, model, stimulated and antagonist group(P<0.05). However, changes of OX1 R exhibited less regularity than orexin-A and was described as following: 6 h: control<stimulated< model< antagonist,12 h: model<antagonist<control<stimulated, 24 h: stimulated<control<model<antagonist, the difference exhibited statistically significance(P<0.05).Conclusion: MNS might be an effective way for TBI-induced coma. The mechanism may be due to upregulating the excitatory hypothalamic neuropeptide orexin-A and OX1 R expression in hypothalamic area.