肌萎缩侧索硬化症中改变了的轴突兴奋性特征:钾通道功能受损与疾病阶段的关系

作     者：Kanai K. Kuwabara S. Misawa S. 赵天智(译) 

作者机构：Department of Neurology Chiba University School of Medicine 1-8-1 Inohana Chuo-ku Chiba 260 -8670 Japan 不详 

出 版 物：《世界核心医学期刊文摘（神经病学分册）》 (Digest of the World Core Medical Journals:Clinical Neurology)

年 卷 期：2006年第2卷第9期

页      面：35-36页

学科分类：1002[医学-临床医学] 100204[医学-神经病学] 10[医学] 

主　　题：肌萎缩侧索硬化症 兴奋性 钾通道 轴突 疾病 功能受损 超极化电流 时间常数 

摘      要：Fasciculations are a characteristic feature of amyotrophic lateral sclerosis (ALS), and can arise proximally or distally in the motor neuron, indicating a widespread disturbance in membrane excitability. Previous studies of axonal excitability properties (i.e. threshold electrotonus, strength-duration time constant)-have suggested respectively that change in potassium or sodium channels may be involved. To reinvestigate these changes and explore their correlation with disease stage, multiple axonal excitability properties (threshold electrotonus, strength-duration time constant, recovery cycle and current-threshold relationship) were measured for the median nerve at the wrist in 58 ALS patients, and compared with 25 age-matched controls. In ALS, there were greater changes in depolarizing threshold electrotonus (i.e. less accommodation) (P 5 mV). Patients with severely reduced CMAP ( 1 mV) alone showed reduced threshold changes to hyperpolarizing current. These results suggest a changing pattern of abnormal membrane properties with disease progression. First, persistent Na+conductance increases, possibly associated with collateral sprouting, and then K+conductances decline. Both changes cause axonal hyperexcitability, and may contribute to the generation of fasciculations. These serial changes in axonal properties could provide insights into the pathophysiology of ALS, and implications for future therapeutic options.