| Project/Area Number |
08672117
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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 |
Functional basic dentistry
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
KARITA Keishiro TOHOKU UNIV., SCHOOL OF DENTISTRY,ASSOC.PROF., 歯学部, 助教授 (40004600)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥2,100,000 (Direct Cost: ¥2,100,000)
Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1996: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | parasympathetic nerve / vasodilatation / hypothalamus / periaquiductal gray / cat / ネコ / 中脳灰白質 / 副交感神経性血管拡張反射 / 抑制効果 |
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| Research Abstract |
The present study investigated the modulation by the anterior hypothalamus (AH) and the periaqueductal gray matter (PAG) of the parasympathetically mediated reflex vasodilatation in lower lip and palate evoked by electrical stimulation of the lingual nerve (LN) in urethane-chloralose-anesthetized and vagosympathectomized cats. Electrical stimulation of the AH and PAG at intensities that did not elicit a pressor effect consistently elicited an intensity (50-500 mA)-dependent attenuation of the lip blood flow increase evoked reflexly by LN stimulation. The optimal stimulus frequency for the inhibitory effect was 50 Hz. The greatest inhibitory effects were evoked from the periventricular region of the anterior hypothalamic area and the PAG at sites in areas A0.5-A2.5. Prior administration of picrotoxin, a relatively specific antagonist of gamma-aminobutyric acid (GABA) receptors, at a dose of 1 mg/kg (i.v.), abolished the inhibitory effect of anterior hypothalamic stimulation completely at any of the stimulus intensities and frequencies used, suggesting that the inhibitory effect of hypothalamic stimulation might be exerted via a GABA-like process effect. Microinjection into the AH of D,L-homocysteic acid (1 M,0.2 ml), an excitatory amino acid, inhibited the lip blood flow increase elicited reflexly by LN stimulation singnificantly. These results suggest that the AH and the PAG are involved in the inhibitory action on the somato-parasympathtic vasodilator reflex in the oro-facial area.
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