Abstract: Objective To explore the effect of vagus nerve stimualtion on wake-promoting and the expression of 5-hydroxytryptamine (5-HT) 2A receptor in the prefrontal contex of coma rats with traumatic brain injury. Methods 72 Sprague-Dawley rats were randomly divided into control group, sham-stimulated group, stimulated group and antagonist group with 18 rats in each group. Traumatic brain injury model was established by a weight-drop head injury. The antagonist group was injected with SB334867, and both the antagonist group and the stimulated group received vagus nerve stimulation. Their behaviors were recorded. And immunohistochemistry technique was used to detect the expression of 5-HT2A receptor in the prefrontal cortex. Results 12 rats in the stimulated group, 9 in the antagonist group and 4 in the sham-stimulated woke up. The expression of 5-HT2A receptor from low to high was ranged as the control group, the antagonist group, the sham-stimulated group and the stimulated group (χ2=11.464, P=0.009). Conclusion Vagus nerve stimulation could raise consciousness in coma rats after traumatic brain injury, which may be related to up-regulating the expression of 5-HT2A receptor.

Key words: traumatic brain injury, coma, vagus nerve stumulation, 5-hydroxytryptamine 2A receptor, orexin-A, rats