| Project/Area Number |
61570738
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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 |
麻酔学
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| Research Institution | Kyoto University |
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Principal Investigator |
HATANO Yoshio Associate professor, Dept. of Anesthesiol. Kyoto University, 医学部, 助教授 (70115913)
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| Co-Investigator(Kenkyū-buntansha) |
MORI Kenjiro Prof. & Chairman, Dept of Anesthesiol. Faculty of Medicine Kyoto University, 医学部, 教授 (20025620)
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| Project Period (FY) |
1986 – 1987
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| Project Status |
Completed (Fiscal Year 1987)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1987: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1986: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | isolated cerebral artery / isolated mesenteric artery / halothane / isoflurane / thiamylal / 脳血流 / イソフルレン |
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| Research Abstract |
The responses of the isolated dog cerebral and mesenteric arteries to anesthetics were compared. Isometric contracations and lrelaxations of helical strips of basilar, middle cerebral and mesenteic arteries (outside diameter, 0.6-0.9 mm), under a resting tension of 1.5 g, were recorded in Krebs' bicarbonate solution aerated with a gas mixture of 95% O_2 and 5% CO_<>. Halothane in concentrations of 0.75 to 2.25% (1 to 3MAC) caused dose-depen-dent relaxation of cerebral arteries while it produced biphasic responses in mesenteric artery: a transient contraction followed by partial relaxation. Isoflurane produced a transient contraction followed by relaxation in cerebral artery. Isoflurane failed to affect the tension of mesenteric artery. Thiamylal in cencentrations of 10^<-5> to 10^<-3> M caused a dose-dependent contraction of cerebral and mesenteric arteries. The thiamylal-induced contraction was significantly greater in cerebral than in mesenteric arteries. The contraction of cerebral and/or mesentric arteries induced by anesthetics studied in the present study was not affected by phentolamine, cinancerin and diphenhydramine but attenuated by nifedipine. The contractions were also attenuated to a greater extent by the exposure of arteries to Ca^<++>-free media for 60 min.
The following conclusions may be made from these findings.
(1) Halothane may dilate cerebral artery more than mesentric artery. The cerebral vasodilation is greater in response to halothane than to isoflurane. These response can occur at clinical concentrations.
(2) Thiamylal causes constrictions of cerebral more than mesenteric arteries. The contraction induced by anesthetics is mediated via Ca^<++> influx from extecellular fluids.
(3) These different responses of isolated arteries from different organs to anesthetics can partially account for the changes of organ blood flow during anesthesia.
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