1994 Fiscal Year Final Research Report Summary
Mechanism of disturbed nerve conduction : analysis of ionic permeability of single myelinated nerve fiber using vaserine-gap voltage clamp technique
| Project/Area Number |
05670555
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Neurology
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| Research Institution | Shiga University of Medical Science |
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Principal Investigator |
YASUDA Hitoshi Shiga University of Medical Science Third Department of Medicine, Assistant Professor, 医学部, 講師 (80135467)
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| Co-Investigator(Kenkyū-buntansha) |
TERADA Masahiko Shiga University of Medical Science, Third Department of Medicine, Instructor, 医学部, 助手 (00227521)
KITASATO Hiroshi Shiga University of Medical Science, Second Department of Physiology, Professor, 医学部, 教授 (20079700)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Motor neuron disease / Diabetic neuropathy / Single myelinated nerve fiber / Voltage clamp / Ion channel / Anti-GM1 antibody / Glucose / Ketone bodies |
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| Research Abstract |
(1) The pathogenic role of anti-GM1 antibody was examined using the vaseline-gap voltage clamp technique on isolated single myelinated rat nerve fibers. Anti-GM1 antisera were obtained from rabbits immunized with GM1 ganglioside. Extracellularly applied anti-GM1 antisera without complement activity increased both the rate of rise and the amplitude of the K+ current elicited with little affect on Na current. In the presence of active complement, anti-GM1 antibodies decreased the Na current, and caused a progressive increase of non-specific leakage current. The results indicate that anti-GM1 antibodies can uncover K^+ channels in the paranodal region and antibody-complement complexes may block Na^+ channels and disrupts the membrane at the Ranvier.
(2) The effect of high glucose, fatty acids and ketone bodies on nerve fibers was examined. After external application of D-glucose, action potential and Na^+ current reduced in amplitude at the concentration of glucose higher than 30 mM.The effect of L-glucose was greater than that of D-glucose. After application of 20mM acetoacetic acid, inward Na^+ current decreased and undershoot markedly increased. The application of 20mM 3-hydroxybutyric acid induced a decrease of Na+ current and an increase of K^+ current. These results suggest that high glucose and ketone bodies play important roles in the development of nerve dysfunction by affecting electrophysiological activity of myelinated nerve fibers.
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