滇重楼多糖对牛蛙心脏和腓肠肌影响的比较研究

A Comparative Study on the Effects of Paris polyphylla Polysaccharide on the Heart and Gastrocnemius of the Bullfrog

目的:探讨不同浓度滇重楼多糖对牛蛙心脏和腓肠肌二者生理特性的影响,并比较其异同。方法:用斯氏蛙心插管法制备离体蛙心,灌流低(1.25 mg/mL)、中(2.5 mg/mL)、高(5 mg/mL)浓度的滇重楼多糖溶液,利用BL-420F生物信息采集处理系统记录给药前后的心肌收缩幅度和心率。制备牛蛙在体坐骨神经-腓肠肌标本,将腓肠肌置于高浓度滇重楼多糖(5 mg/mL)浸泡10 min,记录给药前的标本阈刺激、最大刺激和腓肠肌收缩潜伏期、收缩幅度、收缩时间、舒张时间。结果:滇重楼多糖对牛蛙心脏和坐骨神经-腓肠肌的生理特性影响不同。其中,对牛蛙心肌收缩幅度具有明显的抑制作用(低浓度组P<0.05,中高浓度组P<0.01),但对心率无影响。高浓度滇重楼多糖对牛蛙在体坐骨神经-腓肠肌的阈刺激没有明显影响,但可使其最大刺激极显著增加(P<0.01),对牛蛙腓肠肌收缩潜伏期、收缩幅度、收缩速率和舒张速率均具有明显促进作用(潜伏期P<0.05,其余3项P<0.01)。结论:滇重楼多糖对牛蛙心脏收缩具有抑制作用,对骨骼肌收缩舒张具有促进作用。作用机制可能分别与阻断快INa通道、抑制心肌膜ICa-L进而抑制外Ca2+内流,增强运动单位兴奋性、增加摆动横桥数量、增强钙泵活动等有关。

Objective:To investigate the effects of different concentrations of Paris polyphylla polysaccharide(DRP)on the physiological characteristics of heart and gastrocnemius muscle of the bullfrog,and to compare their similarities and differences.Methods:The isolated frog heart was perfused with the low(1.25 mg/mL),medium(2.5 mg/mL)and high(5 mg/mL)concentration polysaccharide solution of P.polyphylla.The systolic amplitude and heart rate of myocardium before and after administration were recorded by BL-420F biological information collection and processing system.The gastrocnemius muscle of bullfrog in vivo was immersed in high concentration of DRP(5 mg/mL)for 10min,and the threshold stimulation,maximum stimulation,contraction latency,contraction amplitude,contraction time and relaxation time were recorded before administration.Results:The physiological characteristics of the heart and sciatic nerve gastrocnemius muscle of bullfrog were different.Among them,it had obvious inhibitory effects on the amplitude of myocardial contraction of bullfrog(P<0.05 in low concentration group and P<0.01 in medium and high concentration group),but had no effect on heart rate.The high concentration of DRP had no significant effects on the threshold stimulation of sciatic nerve gastrocnemius muscle in vivo,but it could significantly increase the maximum stimulation(P<0.01),and significantly promote the contraction latency,contraction amplitude,contraction rate and relaxation rate of gastrocnemius muscle in bullfrog(P<0.05 in the latency,and P<0.01 in the other three items).Conclusion:The DRP could inhibit the contraction of heart and promote the contraction and relaxation of skeletal muscle.The mechanism of action may be related to blocking the fast ina channel,inhibiting the ICa-L of myocardial membrane,then inhibiting the external Ca2+influx,enhancing the excitability of motor units,increasing the number of oscillating transverse bridges,enhancing the activity of calcium pump,etc.