ABSTRACT
Objective To investigate the changes of sympathovagal balance and the effects of va- gus stimulation on sympathovagal balance in endotoxemia rats.Methods Twenty-four Spragne Dawley rats were randomly divided into four groups.The frequency domain of heart rate variability(HRV)com- ponent was analyzed at 0 min,2 ,4 and 6 hours after intravenous injection of lipopolysaccharide(LPS, 5mg/kg)or physiologic saline,and cervical vagal nerve was stimulated(5mv,2ms,1Hz,5 min lasted, 20 min interval)when LPS or physiologic saline was injected.The levels of Noepinephine(NE)and Ace- tylcholin(ACh)were measured in liver tissues.Results Normalized low frequency(LFnm),hormali- zed high frequency(HFnm),very low frequency(VLF),LF/HF values and liver ACh were significantly increased(P＜0.05)and the level of liver NE was significantly decreased (P＜0.05)after LPS admin- istration.Vagal nerve stimulation markedly increased HFnm but decreased LFnm,VLF,LF/HF values, and the liver ACh also significant increased(P＜0.05 ).Conclusion The results suggest that the ac- tivity of sympathetic and vagal nerve was increased during endotoxemia,but the sympathetic activity was more excitable than that of vagal nerve.Vagal nerve stimulation increased the tone of vagus nerve while the tone of sympathetic nerve was decreased in this study.This may be beneficial for anti-inflammatory activity of vagal nerve.