title: Markedly reduced axonal potassium channel expression in human sporadic amyotrophic lateral sclerosis: an immunohistochemical study.
abstract: Fasciculations are characteristic features of amyotrophic lateral sclerosis (ALS), suggesting abnormally increased excitability of motor axons. Previous nerve excitability studies have shown reduced axonal potassium currents in ALS patients that may contribute to the hyperexcitability and thereby generation of fasciculations. To clarify changes in axonal ion channel expression in motor axons of ALS, we performed immunohistochemistry of potassium and sodium channels in the C7 and L5 ventral/dorsal roots obtained from five autopsy cases of sporadic ALS. Compared to controls, the immunoreactivity of potassium channels (Kv1.2) was markedly reduced in the ventral roots, but normal in the dorsal roots of all the ALS patients. Nodal sodium channel expression was not significantly different in ALS patients and control subjects. Our results show prominently reduced expression of axonal potassium channels, and provide the neuropathological and biological basis for decreased accommodative potassium currents in motor axons of ALS patients. The axonal hyperexcitability would lead to generation of fasciculations, and possibly enhances motor neuron death in ALS.
authors: Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan.
authors: Kazumoto
authors: K
authors: Shibuya
authors: Sonoko
authors: S
authors: Misawa
authors: Kimihito
authors: K
authors: Arai
authors: Miho
authors: M
authors: Nakata
authors: Kazuaki
authors: K
authors: Kanai
authors: Yasumasa
authors: Y
authors: Yoshiyama
authors: Kimiko
authors: K
authors: Ito
authors: Sagiri
authors: S
authors: Isose
authors: Yu-ichi
authors: Y
authors: Noto
authors: Saiko
authors: S
authors: Nasu
authors: Yukari
authors: Y
authors: Sekiguchi
authors: Yumi
authors: Y
authors: Fujimaki
authors: Shigeki
authors: S
authors: Ohmori
authors: Hiroshi
authors: H
authors: Kitamura
authors: Yasunori
authors: Y
authors: Sato
authors: Satoshi
authors: S
authors: Kuwabara
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000378:metabolism* / Q000473:pathology*; D001369:Axons / Q000378:metabolism* / Q000473:pathology*; D005207:Fasciculation / Q000378:metabolism / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D051663:Kv1.2 Potassium Channel / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000378:metabolism / Q000473:pathology; D011940:Receptor Aggregation / Q000502:physiology; D015222:Sodium Channels / Q000378:metabolism; D013126:Spinal Nerve Roots / Q000378:metabolism
chemical_list: D051663:Kv1.2 Potassium Channel; D015222:Sodium Channels