| Project/Area Number |
12671494
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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 | Yokohama City University |
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Principal Investigator |
ANDOH Tomio School of Medicine, Yokohama City University, Associate Professor, 医学部, 助教授 (00193110)
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| Co-Investigator(Kenkyū-buntansha) |
OGAWA Kenichi School of Medicine, Yokohama City University, Lecturer, 医学部, 助手 (10233412)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2000: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | isoflurane / ketamine / ATP sensitive K channel / Substantia Nigra / neuron / brain protection / インフルレン |
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| Research Abstract |
While it is shown that some of general anesthetics have modulatory effects on ATP sensitive K channels (KATP) in cardiac myocytes and smooth muscle cells, their effects on neuronal KATP are poorly understood. We have investigated effects of two different anesthetics on neuronal ATP sensitive K channels (KATP) in rat dopamine neurons located in substantia nigra pars compacts, using a slice patch technique.
We measured the membrane potential and current with the pipette solutions containing ATP either 2 mM, 1 mM or 0 mM. Daizoxide or intracellular ATP depletion by exclusion of ATP from the pipette solution hyperpolarized the neurons and abolished spontaneous action potential firings in a tolbutamide sensitive manner. Isoflurane, a volatile anesthetic, induced a slight depolarization in the presence of intracellular ATP but did not alter the membrane potential after ATP was depleted at 2.2 MAC equivalent Isoflurane at 1 MAC equivalent caused no significant effects in either conditions. Activation of protein kinase C did not influence the effects of isoflurane, unlike to a previous study on cardiac sarcolemmal KATP. Ketamine, an intravenous anesthetic, did not affect the| membrane potential in the presence of ATP 2 mM but partially antagonized hyperpolarization and the outward current caused by ATP depletion at 100 μM. or above.
These results suggest that isoflurane has no significant effects on KATP but ketamine has a blocking action on activated KATP in these neurons.
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