细辛含药血清对SD大鼠DRG神经元I_K的影响

The influence of Asarum medicated serum on the delayed outward potassium current(I_K) in DRG neurons in SD rats

目的探讨细辛含药血清对SD大鼠延髓背侧呼吸中枢(DRG)神经元延迟外向整流钾离子通道(IK)的影响。方法将30只SD大鼠随机分为空白血清组和含药血清组各15只,禁食12h后分别灌服细辛散剂药液和等体积的生理盐水,每日1次,连续8d。末次灌胃2h后眼眶采血。室温下静置30min后取上清液,2500r/min离心25min,分离血清,置于56℃水浴30min灭活,过0.22μm微孔滤膜滤过除菌,分装,-20℃条件下保存备用。鼠龄1-3d的SD大鼠,雌雄不限,采用膜片钳WCR,分别记录空白对照组、空白血清组和含药血清组大鼠DRG神经元IK的变化。结果空白血清组与空白对照组相比,无显著性差异(P>0.01),而细辛含药血清与空白对照组、空白血清组相比均有非常显著性差异(P<0.01)。各组大鼠DRG神经元IK的生物特性无明显变化。结论细辛对延髓DRG呼吸神经元延迟外向整流钾离子通道(IK)的激活作用可能是细辛抑制呼吸中枢的离子机制之一。

Objective: To observe the influence of Asarum medicated serum on the delayed outward potassium channel in isolated SD rat's medulla DRG neurons.Methods 30 SD rats were randomized into control serum group(n=15) and medicated serum group(n=15).After 12 hours fasting,rats of different groups were given respectively Asarum powder and normal saline in equal volume via gastric perfusion,once a day for consecutively 8 days.Orbital blood sampling was performed at 2 hours after final gastric perfusion.The supernatant was attained at room temperature at 30 minutes after blood collection,then underwent centrifuge at 2500r/min for 25 minutes to isolate serum and deactivated at 56℃ for 30 minutes,removing bacteria were filtered(0.22μm) and then the attained serum was stored at-20℃.SD rats were 1 to 3 days old,male or female.Changes of delayed outward potassium current(IK) of control group,control serum group and medicated serum were recorded with patch-clamp technique in WCR configuration.Results Significant difference was not observed between control serum group and control group(P>0.05) but demonstrated in comparisons between Asarum medicated serum group and the other two groups(P<0.01).And no obvious change in biological characteristics of the delayed outward potassium channel was observed.Conclusion The activation of the delayed outward potassium channel of medullary inspiratory neurons of dorsal respiratory group may be one of the ionic mechanisms for central respiratory inhibition by Asarum.