| Project/Area Number |
61480098
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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 |
General physiology
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| Research Institution | MIE UNIVERSITY |
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Principal Investigator |
NOSAKA Shoichiro PROFESSOR, SCHOOL OF MEDICINE , MIE UNIVERSITY, 医学部, 教授 (00025595)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Takeshi LECTURER, SCHOOL OF MEDICINE , MIE UNIVERSITY, 医学部, 講師 (90106972)
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| Project Period (FY) |
1986 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥6,500,000 (Direct Cost: ¥6,500,000)
Fiscal Year 1988: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1987: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1986: ¥4,500,000 (Direct Cost: ¥4,500,000)
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| Keywords | Vagus nerve / Cardioinhibitory center / Noxious somatic sensation / Hypothalamic defense area / Arterial baroreflex / Nucleus ambiguus / Dorsal motor nucleus / 順応現象 / 変時作用 / 変力作用 / ペーシング / カイニン酸 / 迷走神経心臓枝 / 心拍同期性 / 呼吸同期性 / 吻側延髄腹外野 / GABA / 大動脈神経 / 迷走神経性徐脈 / 坐骨神経 / 抑制性上行路 / 抑制性下行路 |
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| Research Abstract |
Integrativemechanisms regulating vagal cardioinhibitory center (VCIC) as well as its functional characteristics were studied in chloralose-urethane anesthetized rats. The results obtained are summarized as follow. Project-1986. 1. It was found that baroreflex vagal bradycardia (BVB) due to aortic depressor nerve (ADN) stimulation is remarkably suppressed by stimulation of the sciatic nerve (ScN) and hypothalamic defense area (HDA). 2. Spinal ascending pathways mediating ScN inhibition of BVB are bilateral projections with multifold combinations of midline crossing at spinal and/or medullary level. 3. Descending pathways mediating HDA inhibition of BVB are also bilateral; ipsilateral one coursing through the periventricular gray, parabrachial nucleus and lateral pontine reticular formation to project to VCIC. 4. Analysis of influence of ScN and HDA on field potential evoked by ADN and vagus cardiac branch (VCB) stimulation revealed that target cells of ScN and HDA inhibition of BVB are
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preganglionic cells of VCIC. These inhibitions are GABA-mediated. Project-1987. 1. It was found that BVB shows a rapid adaptation when ADN is repetitively stimulated. 2. Cardiac rhythmicity was augmented when the heart was artificially slowed, suggesting that adaptation of BVB always functions to reduce cardiac rhythmicity of VBC. 3. Such apaptation of BVB is GABA-mediated. 4. Brainstem stimulation study revealed that there are mutual inhibitory interaction between VCIN and its sympathetic counterpart, vasomotor center in the rostral ventrolateral medulla. Project-1988. 1. Assessment of cardioinhibitory functions of two subnuclei of VCIN, the nucleus ambiguus and dorsal motor nucleus was attempted. Microstimulation of one of the two following kainate destruction of the other provoked bradycardia and diminished atrial contractility, but did not affect ventricular contractility. These effects on contractility was confirmed while the heart was paced. It is concluded that cardioinhibitory functions are shared by the two nuclei and there is no qualitative difference in their cardioinhibitory functions. Less
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