大鼠背根节内两类兴奋性神经元的放电特征

Firing characteristics of two classes of neurons in rat DRG

目的 :观察大鼠背根节 (DRG)神经元兴奋性分类的放电特征 .方法 :在新鲜分散的中、小型大鼠背根节神经元运用全细胞膜片钳技术 ,观察给予胞内去极化 ,超极化电流刺激引起细胞放电的特征 .结果 :根据大鼠背根节神经元的放电特征可将它们区分为两类兴奋性 .1类 :神经元兴奋性与刺激强度相关 ,逐渐增强的去极化刺激可引发频率由低到高的动作电位 .一般于超极化刺激后不产生反跳动作电位 .动作电位的幅值一致 ,符合“全或无”定律 .2类 :神经元的兴奋性与去极化刺激强度关系不明显 ,神经元放电频率比较稳定 ,不随刺激强度的增强而增加 ,放电前后有规律的膜电位振荡 .于较弱的超极化刺激后可产生反跳动作电位 .动作电位的幅值不一致 .结论 :大鼠DRG两类兴奋性神经元各具不同的放电特征 .

AIM: To study the characteristics of firing in rat dorsal root ganglia (DRG) neurons by neural excitability. METHODS: Whole cell patch clamp experiments were performed with medium and small DRG neurons freshly isolated from rats. RESULTS: The firing characteristics of the two classes of cells were: In class 1, all or none action potentials could be generated with arbitrarily low frequency and the frequency increased with the increased current. No firing responded to weak inhibitory pulse. In class 2, the action potentials were generated in a certain frequency band that was relatively insensitive to the strength change of the applied current. Regular membrane potential oscillations emerged before and after firing, indicating spikes were not all or none, and post inhibitory spikes could be found. CONCLUSION: The two classes of rat DRG neurons have their own characteristics of firing.