经皮穴位电刺激对跑台运动大鼠血浆氨基酸及中缝背核细胞外液5-HT含量的影响

目的:探讨经皮穴位电刺激(TEAS)对急性跑台运动大鼠血浆氨基酸及中缝背核(DRN)细胞外液5-HT含量的影响。方法:20只雄性SD大鼠行DRN立体定位术后,随机分为运动组(n=10)和TEAS组(n=10)。术后第2天,所有大鼠开始接受适应性运动,TEAS组介入TEAS治疗,取右侧足三里穴进行电针治疗,参数为连续波,频率2Hz,强度5mA,时间30min,每日1次,连续治疗6天。术后第7天,行微透析采样,收集基础液后进行急性跑台运动(先以10m/min的速度运动10min,在随后4min内将跑速调至24m/min并持续运动1h,坡度为0),微透析采样直至运动后5h。记录运动中毛刷刺激频次;采用脑微透析采样技术和高效液相电化学法(HPLC-ECD)连续观察运动前后大鼠DRN细胞外液5-HT水平动态变化;运动后5h时,采用高效液相紫外法(HPLC-UV)检测血浆氨基酸含量。结果:(1)TEAS组毛刷刺激频次显著低于运动组(P<0.05)。(2)与运动组比较,TEAS组大鼠血浆总色氨酸(T-TRP)和支链氨基酸(BCAA)含量变化不明显(P>0.05),而血浆游离色氨酸(f-TRP)含量(P<0.01)、f-TRP/T-TRP(P<0.01)和f-TRP/BCAA比值(P<0.05)显著降低。(3)运动组运动后即刻DRN细胞外液5-HT水平显著高于基础水平(P<0.05),在随后2h内降低,而在运动后3h和4h时又呈升高趋势,显著高于运动后2h时;TEAS组在运动后各时段均低于运动组,尤以运动后5h为显著(P<0.05)。结论:TEAS足三里穴可有效提高大鼠运动能力,可能通过降低血浆TRP游离度和f-TRP转运入脑,进而减少脑内5-HT的部分合成实现的。

Effects of Transcutaneous Electrical Acupoint Stimulation on the Plasma Amino Acid and Extracellular 5-HT in Dorsal Raphe Nucleus of Exercising Rats

Objective To observe the effect of transcutanous electrical acupoint stimulation(TEAS)on the exercise ability of rats.Methods After stereotaxis surgery,twenty male adult SD rats wera randomly divided into control group (n=10)and TEAS group(n=10).Two days after surgery.the rats were trained to adapt the treadmill mnning and TEAS(continuous wave,2Hz,5mA)was applied to right "Zusanli" (ST 36) for 30min,once a day for 6 days.Basic microdialysis samples of extracellular serotonin(5-HT)in rats'dorsal raphe nucleus(DRN)were collected 7 days after surgery.During experiment,rats were running on treadmill (10m/min for 10min,then gradually increased to 24m/min for 1 hour,0% grade).Microdialysis samples were collected continuously until 5 hours after treadmill running.The frequency of brush-stimulation during the running was recorded.Meanwhile,plasma amino acid content was examined 5 hours after exercise.Results The frequencies of brush-stimulation during the treadmill running in control group and TEAS group were 2.04+0.46 and 0.40+0.080 times per minute,respectively (P<0.05).There were no significant differences in plasma total-TRP(T-TPP)and branched chain amino acid(BCAA)contents between two groups(P>0.05).However,plasma free-TRP(f-TRP)content,f-TRP/T-TRP ratio and f-TRP/BCAA ratio decreased significantly(P<0.05) in TEAS group as compared with the control group.Extracellular 5-HT levels in DRN in control group soon after exercise were higher than their base levels(P<0.05),and decreased in sequential two hours,and then increased significantly 3 hours and 4 hours after exercise as compared with that 2 hours after exercise(P<0.05).There was a slow decline in the levels of extracellular 5-HT in TEAS group at each time-point after exercise,and significant lower than that in control group within 5 hours after exercise(P<0.05).Conclusion TEAS at"Zusanli"(ST36)can effectively improve exercised ability by reducing peripheral free-TRP level and transporting TRP into the brain,and thus decreasing the synthesis of 5-HT in the brain.