1991 Fiscal Year Final Research Report Summary
Study on Mechanism of the Autonomic Nerve Reflex induced by Nociceptive Stimulation in the Orofacial Region.
| Project/Area Number |
02454454
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
外科・放射線系歯学
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
KUBOTA Yasuya Tokyo Medical and Dental University Dept. of Dental Anesthesiology Professor, 歯学部, 教授 (90013804)
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| Co-Investigator(Kenkyū-buntansha) |
OHWATARI Tsuneto Tokyo Medical and Dental University Dept. of Gerodontics Research Associate, 歯学部, 助手 (80194322)
KATAKURA Nobuo Tokyo Medical and Dental University Dept. of Dental Anesthesiology Research Asso, 歯学部, 助手 (20185804)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Trigemino-autonomic reflex / trigemino-sympathetic reflex / trigemino-vagal reflex / the hypothalamic defense area / microinjection of lidocaine / the spinal trigeminal nucleus / the ambiguus nucleus / the dorsal motor nucleus of the vagal nerve |
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| Research Abstract |
Effects of stimulation of the hypothalamic defense area on the trigemino-autonomic reflex (TAR) were studied in chloralose-anesthetized cats. The reflex discharges were recorded from the cervical vagal nerve (CVN), and the cardiac branch of the vagal nerve (CBV) in response to electrical stimulation of the inferior alveolar nerve (IAN). The following results were obtained. 1) The discharge in the CBV evoked by the IAN stimulation was completely abolished by transection of the cervical spinal cord, while it was not affected by section of the CVN. Thus the TAR in the CBV wholly consisted of the sympathetic nerve discharge (Trigemino-sympathetic reflex, TSR). 2) The TAR recorded from the CVN (Trigemino-vagal reflex, TVR) was depressed by repetitive simulation of the hypothalamic defense area. The threshold was below that for induing cardiovascular changes. Short train pulse applied to the hypothalamic defense area suppressed the TVR for about 200ins with a peak at about 40ms. It is sugges
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ted that the hypothalamic effect of the TVR was centrally induced and not the secondary effect of cardiovascular changes. 3) The TSR showed no definite changes in response to repetitive stimulation of the hypothalamic defense area. The results support the notion that the TAR is centrally integrated to suit the cardiovascular system to the needs of the organism in defense reaction.
The output site of the TVR in the brainstem were studied in chloralose-anesthetized cats. The reflex discharges were recorded from the CVN in response to electrical stimulation of the trigeminal ganglion (TG). The following results were obtained. 1) The TVR recorded from the CVN was depressed by microinjection of lidocaine in the ambiguus nucleus (AN), but not completely abolished. 2) The TVR recorded from the CVN was also depressed by microinjection of lidocaine in the dorsal motor nucleus of the vagal nerve (DMV), but not completely abolished. These results suggested that the AN and the DMV are both final outputs of the TVR reflex arc from the central nervous system.
The primary site of the TAR in the brainstem were studied in rats anesthetized with thiamylal sodium. The blood pressure changes induced by electrical stimulation of the tooth pulp and the tongue were recorded from the femoral artery. The following results were obtained. 1) Blood pressure raised by stimulation of the tooth pulp and the tongue in proportion to stimulation intensity. No hypotension was induced during the stimulation. 2) Blood pressure changes evoked by the simulation of the tooth pulp and the tongue were depressed by microinjection of lidocaine in the spinal trigeminal nucleus (STN) all along the neuraxis including the caudal part of the STN. These results suggested that the caudal part of the STN plays an important role of the cardiovascular changes induced by stimulation of the trigeminal nerve. Less
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