Effect Of Xiao-Ban-Xiao-Tang On The Subdiaphragmatic Vagal Afferent Discharge In Chemotherapy-induced Vomiting Model Rats

Objective : To reasearch the effect of Xiao-Ban-Xia-Tang on the chemotherapy-induced vomiting model rat by recording the discharge of subdiaphragmatic vagus nerve, in order to explore the antiemetic mechanism of Xiao-Ban-Xia-Tang. Methods: SD rats were divided into normal control group, model group, positive drug treatment groups, Xiao-Ban-Xia-Tang treatment group(high, middle and low dose group), Xiao-Ban-Xia-Tang normal control group. The chemotherapy-induced vomiting model rats were established by jugular vein injection cytotoxic chemotherapy drug(cisplatin), 5-HT3 receptor selective agonist 1-phenylbiguanide(1-PBG) and NK1 receptor agonist(substance P) respectively. Three days before the experiment begining preventive administration, Xiao-Ban-Xia-Tang treatment groups(high, middle, low dose group) were given Xiao-Ban-Xia-Tang of 3.2 g/kg, 1.6 g/kg,0.8 g/kg, the positive drug groups were given ondansetron 2.6 mg/kg, aprepitant 11.08 mg/kg, Xiao-Ban-Xia-Tang normal control group were given Xiao-Ban-Xia-Tang 1.6 g/kg, the normal control group and model group were given the same volume of distilled water every day, the daily dose was divided into twice(12 h interval). The third day(the fifth administration 1 hour later) animals were anesthetized, spliting the jugular vein for administrating the tool drugs, separating subdiaphragmatic vagus nerve for recording the rat subdiaphragmatic vagus nerve discharge after injected tool drugs cisplatin, 1-PBG and substance P, at the same time monitoring the ECG and rectal temperature at 38?. Results: After injection cisplatin, 1-PBG and substance P respectively, the subdiaphragmatic vagal discharge activity of model group were significantly enhanced(P<0.001); Xiao-Ban-Xia-Tang(high and middle dose group) could inhibit the subdiaphragmatic vagal discharge activity caused by the tool drugs(P<0.001), and showed a certain dose effect relationship, Xiao-Ban-Xia-Tang high-dose inhibited the increase of the discharge of subdiaphragmatic vagus nerve, which had the strongest effect and significantly stronger than the positive drug ondansetron and aprepitant(P<0.001). Couclusion : Xiao-Ban-Xia-Tang could significantly inhibit the increase of subdiaphragmatic vagus nerve discharge activity after injected cisplatin, 1-PBG and substance P, respectively, the results implied that Xiao-Ban-Xia-Tang could block 5-HT3 receptor and NK1 receptor in subdiaphragmatic vagus nerve, and inhibited impulse from vagus afferent nerve transferred to vomiting center, which could be underlying mechanim of Xiao-Ban-Xia-Tang to prevent and treat chemotherapy-induced nausea and vomiting.