1998 Fiscal Year Final Research Report Summary
The research for voltage-gated K+ channel abnormality in peripheral nerve disorders.
| Project/Area Number |
09670662
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Neurology
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| Research Institution | Kagoshima University |
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Principal Investigator |
ARIMURA Kimiyoshi Faculty of Medicine Kagoshima University, Associate Professor, 医学部, 助教授 (20159510)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAGAWA Masanori University Hospital Kagoshima University, Assistant Professor, 医学部・附属病院, 講師 (50198040)
KAMEYAMA Masaki Faculty of Medicine Kagoshima University, Professor, 医学部, 教授 (60150059)
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| Project Period (FY) |
1997 – 1998
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| Keywords | muscle cramp / myokymia / K+ channel / Na+ channel / Isaacs' syndrome / anti VGKC antibody / western blot / immunoprecipitation |
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| Research Abstract |
We studied the suppression of K current by patch clamp method and the existance of anti-VGKC antibodies by western blot (WB) and imrnunoprecipitation (IP) methods in sera from 21 patients with muscle cramp, myokymia and myokymic discharges using cultured cells. In 7 Isaacs' patients, 3 of 7 sera were WB positive and all sera suppressed K current. In 14 other patients, 6 of 14 sera were WB positive and all these sera suppressed K current. Myokymic discharge are frequently seen in patients with the suppression of K current. Only 4 of 14 patients showed IP positive whereas 8 of 14 patients showed WB positive. These findings indicate that anti-VGKC antibodies are not specific for Isaacs' syndrome but are also positive in patients with idiopathic generalized myokymia. IP assay using for detecting anti-channel antibodies in MG and LEMS is not useful for Isaacs' syndrome. From the results of patch clamp studies using of VGKCs (kv 1.1 and 1.6) cDNA transfected cells, the activation kinetics of VGKC were not changed by anti-VGKC antibodies, but total number of VGKC was decreased. Regarding the correlation between anti-ganglioside antibodies (AGA) and conduction block, we could not find the suppression of Na current in sera form 4 GBS patients with positive AGA.We conclude that AGA may not correlate with conduction block due to Na channel suppression.
From our studies, the anti-VGKC antibodies play an important role in neuropathic patients with nerve hyperexcitability and these patients may categorize as potassium channelopathy.
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