| Project/Area Number |
14571473
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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 |
Anesthesiology/Resuscitation studies
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| Research Institution | Nippon Medical School |
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Principal Investigator |
KIM Chol Nippon Medical School, Dept of Anesthesiology, Assistant Professor, 医学部, 助手 (80318493)
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| Co-Investigator(Kenkyū-buntansha) |
TAKEDA Shinhiro Nippon Medical School, Dept of Anesthesiology, Lecturer, 医学部, 講師 (00247008)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2004: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2003: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2002: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Keywords | carotid body / benzodiazepine / hypoxic respiratory response / oxygen sensing mechanism / ミダゾラム / 活動電位 / 国際情報交換 / スウェーデン |
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| Research Abstract |
Background : While the contribution of the gamma-amino butyric acid (GABA) receptor system in peripheral chemosensation is unclear, immunohistochemistry has pointed out the presence of GABA-ergic receptors in mammalian carotid bodies. We hypothesized that an activation of the carotid body GABA receptors would counteract the depolarizing effect of hypoxia.
Methods : The carotid body with arterial supply and the carotid sinus nerve was removed en bloc from the New Zealand White Rabbits and was placed in a perfusion chamber. The carotid body preparation was perfused via the cut common carotid artery with a modified Tyrode's solution at a rate of 3.5-4.5 ml/min with constant pressure of 45 cm H_2O. The carotid sinus nerve firing frequency (Hz) was recorded at two different oxygen tension levels during perfusion with midazolam of 1,10, and 100 μg/L.
Results : The frequency was reduced by midazolam in a dose dependent manner (n=8). Firing frequencies at low oxygen tension level decreased from 643.13 +/- 67.2 Hz in control, to 554.5 +/- 67.7 (P= 0.054, vs. control), to 509.01 +/- 100.5 (P<0.012, vs. control), and to 422.6 +/- 77.3 (P<0.001, vs. control) during perfusion with midazolam 1,10 and 100 μg/L respectively (mean +/- SEM).
Conclusion : Midazolam depresses carotid body chemoreceptor activity in a dose dependent manner.
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