| Project/Area Number |
09672031
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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 |
Surgical dentistry
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| Research Institution | HOKKAIDO UNIVERSITY |
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Principal Investigator |
KAMEKURA Nobuhito Dental Hospital, Hokkaido Univ., Lec., 歯学部・附属病院, 講師 (80214550)
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| Co-Investigator(Kenkyū-buntansha) |
AKAIKE Tadashi School of Dent., Hokkaido Univ., Pro., 歯学部, 教授 (70010105)
FUKUSHIMA Kazuaki Dental Hospital, Hokkaido Univ., Pro., 歯学部・附属病院, 教授 (00002361)
KAMADA Tsutomu School of Dent., Hokkaido Univ., Inst., 歯学部, 助手 (20091431)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1998: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | TRIGEMINAL NERVE / AUTONOMIC NERVE / GENERAL ANESTHETICS / ISOFLURANE / SOVOFLURANE / PROPOFOL / TRIGEMINAL DEPRESSOR RESPONSE |
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| Research Abstract |
We investigated effects of general anesthetics on trigeminal depressor responses ( TDR), which were evoked with electrical stimulation to trigeminal nerve.
These studies were performed on adult Japanese White rabbits, anesthetized with urethane and alfa-chioralose. The trachea was cannulated and a catheter placed in femoral artery. Arterial pressure and heart rate were calculated from pressure wave of femoral artery. Mental nerve was stimulated with 10S train of squarewave pulses (0.5mS duration). Records of nerve activities were obtained from cervical sympathetic nerve and vagal nerve.
In preliminary study, we determined that the optimal frequency and intensity range which evoked trigeminal depressor response was 5Hz and 5-20mA.In this study, mental nerve was stimulated in these manners.
We examined two volatile anesthetics (isoflurane and sevoflurane ) and one intravenous anesthetic (propofol).
In isoflurane and sevoflurane, degree of fall in blood pressure became smaller as inspired concentration of anesthetics became higher. TDR disappeared in almost 0.75-1.0 MAC ( tail clamp method). 1.0 MAC of tail calmp method is said to be equivalent to plane 3 or 4 of third stage in Guedel's clinical signs. It is suggested that concentration necessary to suppress TDR is rather high in isoflurane and sevoflurane.
On the other hand, effects of propofol on TDR were minimum. In administration rate of 125 mg/kg/hr, which was extremely high dosage, about 8% of fall in blood pressure evoked with mental nerve stimulation was observed. So we concluded that propofol could not disappear TDR completely. It is suggested that proper blocked of noxious stimulation is necessary when general anesthesia is performed with propofol for oral surgery.
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