局部注射αβme-ATP对大鼠背部皮肤初级传入纤维的兴奋作用  

Local injection of alpha, beta-methylene ATP induces excitation of primary afferent fibers in rats

作　　者：张琪[1] 赵晏[1] 田雨灵[1] 郭媛[1] 曹东元[1] 王会生[1] 

机构地区：[1]西安交通大学医学院生理学和病理生理学系环境与疾病相关基因教育部重点实验室,陕西西安710061

出　　处：《第一军医大学学报》2005年第10期1256-1260,共5页Journal of First Military Medical University

基　　金：国家自然科学基金(30371729;30400131);教育部高校博士点基金(20020698033;20040698022);陕西省自然科学基金(2004C225)~~

摘　　要：目的探讨P2X嘌呤受体激动剂αβme-ATP对大鼠背部皮肤感受单位的兴奋和敏化作用.方法在大鼠T9～Ti3脊神经背侧皮支分离细束,进行单纤维电生理学记录,观察相应皮肤感受野注射αβme-ATP(100 μmol/L,10μl)或生理盐水对皮肤感受单位机械阈值和自发放电的影响及时程变化.结果①Aδ和C类纤维的机械阈值分别是(0.384±0.018)和(0.943±0.102)mN,注射αβme-ATP后降低至(0.304±0.013)和(0.659±0.071)mN(P＜0.05,P＜0.01);Aβ纤维的机械阈值是(0.301±0.019)mN,注射αβme-ATP后为(0.288±0.018)mN(P＞0.05).生理盐水对照组注射前后Aβ、Aδ和C类纤维的机械阈值均无显著变化(P＞0.05).②注射αβme-ATP后,Aβ、Aδ和C类纤维自发放电频率增加的比例分别为7.7%、66.7%和75.0%,其中Aδ和C类纤维的反应比例显著高于Aβ纤维(P＜0.01).生理盐水对照组未见自发放电频率显著增加的单位.③Aδ和C类纤维在注射αβme-ATP过程中(5 min)的平均自发放电数和注射后(5 min)的平均自发放电数与注射前相比均显著增加(P＜0.05),但Aβ纤维在注射过程中平均自发放电数和注射后平均自发放电数与注射前相比无显著性差异(P＞0.05).另外,还观察了αβme-ATP引起感觉神经自发放电的时程变化,发现αβme-ATP对Aδ和C类初级传入末梢的兴奋作用可见于所观察的整个时段.结论ATP的类似物αβme-ATP对大鼠背部皮肤的Aδ和C类纤维具有兴奋和敏化作用.Objective To observe the excitation and sensitization of dorsal cutaneous primary afferent fibers induced by P2X agonist alpha, beta-methylene ATP （αβme-ATP） in rats. Methods By means of single fiber electrophysiological recordings on the nerve filaments isolated from the dorsal cutaneous branches of the T9-T13 spinal nerves, the effects of αβme-ATP （100 μmol/L, 10 μl） injection into the cutaneous receptive field on the mechanical threshold and spontaneous discharge of rat primary sensory afferent units were observed. Results The mean mechanical threshold of Aδ and C fibers prior to αβme-ATP injection were 0.384±0.018 and 0.943±0.102 mN, and lowered to 0.304±0.013 and 0.659±0.071 mN after the injection, respectively （P〈0.05, P〈0.01）, The mechanical threshold of the Aβ fibers before αβme-ATP injection was 0.301±0.019 mN, and slightly lowered to 0.288±0.018 mN after the injection （P〉0.05）. Injection of αβme-ATP （10 μl） into the receptive fields evoked spontaneous discharge in 7.7% of the Aβ fibers, 66.7% of Aβ fibers and 75.0% of C fibres, respectively, and the proportions of Aβ and C fibers with spontaneous discharge evoked by αβme-ATP were significantly greater than that of Aβ fibers （P〈0.05）. In the control experiments, injection of saline did not significantly affect spontaneous discharge or excite the nerve fibers. The mean discharge frequency of Aδ and C fibers increased from 0.73±0.24 and 0.54±0.21 impulses/min before injection to 3.05±0.65 and 8.53±2.04 impulses/min during the injection, with subsequent reduction to 2.40±0.60 and 6.68±1.68-impulses/min in the following 5 min （P〈0.05）, In contrast to Aδ and C fibers, Aβ fibers exhibited no significant changes in the mean discharge frequency in response to αβme-ATP （0.23±0.09 impulses/min before injection, 0.28±0.09 impulses/min during injection and 0.22±0.14 impulses/min after injection, P〉0.05）. The excitatory effects of αβme-ATP on the discharge rate in Aδ and C primary

关 键 词：αβme-ATP P2X嘌呤受体 外周神经 伤害感受单位 外周痛敏化 

分 类 号：Q432[生物学—生理学]