不同刺激方式对在体和离体蛙腓肠肌单收缩影响的定量分析

Quantitative analysis of the effects of different stimuli on the contraction of gastrocnemius in vivo and in vitro specimen

目的:自编程定量分析不同电刺激方式对在体和离体蛙腓肠肌单收缩的影响。方法:实验分为四个组:间接刺激在体标本组(n=12),直接刺激在体标本组(n=8),间接刺激离体标本组(n=12),直接刺激离体标本组(n=8)。分别制备在体和离体蛙腓肠肌标本,施以间接电刺激(经坐骨神经)或直接电刺激(细针灸针刺激电极直接刺入腓肠肌中):强度从0 V开始,周期3 s,增量0.02 V,刺激150次;用生物机能实验系统(BL-420F)实时记录不同强度刺激对肌肉收缩的影响。后续通过自编程辅助处理分析肌肉收缩数据,对单收缩特征参数进行定量比较分析。结果:①对在体标本,与直接刺激比较:间接刺激的阈强度、半高强度和最适强度均更小(P<0.05);最大单收缩幅度更大,收缩期更长,上升斜率更小(P<0.05)。②对离体标本,与直接刺激比较:间接刺激的阈强度、半高强度和最适强度也均更小(P<0.05);最大单收缩幅度更大,收缩期更长,上升斜率更小(P<0.05)。③均采用间接刺激或直接刺激时,与离体标本比较,在体标本单收缩的各项参数均无差异(P>0.05)。结论:不论使用间接刺激或是直接刺激,在体标本和离体标本的单收缩功能特点均无显著差异;但间接刺激比直接刺激更容易触发腓肠肌产生单收缩,且单收缩幅度更高。

Objective:To quantitatively analyze the effects of direct and indirect stimuli on the contraction of gastrocnemius in vivo and in vitro specimen by self-programming.Methods:All specimens were divided into four groups:indirect stimuli on specimen in vivo group(n=12),direct stimuli on specimen in vivo group(n=8),indirect stimuli on specimen in vitro group(n=12),direct stimuli on specimen in vitro group(n=8).Indirect stimuli(via sciatic nerve)and direct stimuli(acupuncture needle piercing into gastrocnemius)(stimuli starting from 0 V,cycle 3 s,increment 0.02 V,150 times)were acted on in vivo and in vitro sciatic nerve gastrocnemius muscle specimen respectively.The effects of electric intensity on the contraction of gastrocnemius were recorded by the experimental system of BL-420F.The data were processed and analyzed by the help of self-programming,to quantitatively obtain key parameters for a single contraction.Results:①For in vivo specimen,compared with direct stimuli,effects of indirect stimuli were as follows:the threshold intensity,half-intensity and maximal intensity of the specimen were smaller(P<0.05);the amplitude was larger,the contraction period was longer,and the rising slope was smaller(P<0.05).②For in vitro specimen,compared with direct stimuli,effects of indirect stimuli were as follows:the threshold intensity,half-intensity and maximal intensity of indirect stimuli were smaller(P<0.05);the amplitude was larger,the contraction period was longer,and the rising slope was smaller(P<0.05).③Compared with in vitro specimen,there was no significant difference among all the above parameters of in vivo specimen,with either direct or indirect stimuli(P>0.05).Conclusion:There is no significant difference in the features of single contraction between in vivo and in vitro specimen with either direct or indirect stimuli.However,indirect stimuli can trigger gastrocnemius to produce single contraction more easily than direct stimuli,and the amplitude is larger than that of direct stimuli.