Effects Of Granisetron On Vasovagal Syncope On Rabbits

Objective To study the effects of granisetron on vasovagal syncope(VVS) in rabbits.Method Twenty-four healthy New Zealand rabbits were divided randomly into a control group and an intervention group,12 in each group. The rabbits in the control group and in the intervention group were injected intravenously with normal saline and granisetron, respectively. In the established VVS models, each rabbit received bloodletting at 4 time points:T1,T2,T3,T4. Compare the bloodletting time, the concentration of 5-hydroxytryptamine(5-HT) at T1,T2,T3,T4 and the total blood volume between the groups. The heart rate and blood pressure were monitored during the entire process. The data were analyzed by statistics .Result 1.The bloodletting time at T2,T3 and T4 was significantly longer in the intervention group than that in the control group (P<0.01). 2.The mean blood pressure and the heart rate at T2 between the two groups were not significantly different. 3.In the control group the concentration of 5-HT at T3 was significantly different from that at T1(P<0.0001). This was also true at T4 versus T3(P<0.001).Whereas,the concentration at T1,T2,T3 between the two groups was similar, except at T4 (P<0.01). 4.The total blood volume at T4 in the intervention group was more than that in the control group [(76.10±15.36)mL vs (55.30±13.52)mL,P<0.05]. 5.At the end of the experiment 10 rabbits in the control group developed convulsion and eventually blood pressure and the heart rate vanished resulting in death (83%). However, 11 rabbits in the intervention group did not develop convulsion and died of breathing arrest (92%).Conclusion Granisetron can weaken or prevent Bezold-Jarisch reflex and can improve the endurance of cerebral ischemia and blood-supply deficiency. Granisetron can serve as the medicine to prevent or cure VVS .