2006 Fiscal Year Final Research Report Summary
Effect of sevoflurane on the voltage-dependent sodium currents in a Lymnaea neuron
Project/Area Number |
17591641
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Single-year Grants |
Section | 一般 |
Research Field |
Anesthesiology/Resuscitation studies
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Research Institution | University of Miyazaki |
Principal Investigator |
ONIZUKA Shin University of Miyazaki, Faculty of Medicine, Associate Professor, 医学部, 助手 (20264393)
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Project Period (FY) |
2005 – 2006
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Keywords | Sevoflurane / Internal perfusion / Sodium currents / リドカイン / ナトリウムチャネル |
Research Abstract |
Background : The voltage-dependent sodium currents (INa^+) are related to neuron excitability and anesthesia. To clarify the anesthetic mechanism of sevoflurane affecting INa^+, the effects of sevoflurane and lidocaine on INa^+ were compared using a neuron from Lymnaea stagnalis. Methods : The effects of sevoflurane and lidocaine on the membrane potential and INa+ were measured using current clamp and whole cell patch-clamp configuration. Sevoflurane was perfused either extra-cellularly or intra-cellularly. The amplitude of action potential, current voltage curves, and steady-state inactivation curves for INa+ were measured following in external and internal perfusion of sevoflurane. Results : External perfusion with sevoflurane suppressed the amplitude of the action potential [61.8 ± 7.6 (mV) in the controls, 43.8 ± 7.1 at 0.4 mM, 4.8 ± 3.6 at 2 mM, and 0.9 ± 0.8 at 4 mM], and INa^+ [80 ± 11% at 0.4 mM, 59 ± 12 % at 2 mM, and 48 ± 12 % at 4 mM] in a concentration-dependent manner. However, with internal perfusion, sevoflurane did not suppress these parameters. Conversely, internal perfusion of lidocaine suppressed INa+. The steady-state inactivation curves were not shifted by either external or internal perfusion of sevoflurane as lidocaine. Conclusion : Sevoflurane acts as an extra-cellular plug to suppress the voltage-dependent sodium currents.
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