1987 Fiscal Year Final Research Report Summary
Localization and function of the respiratory central chemosensitive areas by occlusion of the arteriesand injection of hypercapmic blood into the the asterieson the ventral sufrace of the medulla in anesthetixed cats.
| Project/Area Number |
61570053
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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 |
General physiology
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| Research Institution | Teikyo University |
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Principal Investigator |
MATSUI Teijito Teikyo Unversity, School of Medicine (asso. Prof)., 医学部, 助教授 (80082098)
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| Co-Investigator(Kenkyū-buntansha) |
桑名 俊一 帝京大学, 医学部, 助手 (70129998)
TEIKYO Unversity School
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| Project Period (FY) |
1986 – 1987
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| Keywords | Respiratory central chemosensitive area / %pharenic nerve actibty / Micto pH glass-eceltrode / Occlustion of atr.carotis externa and Att / basilaris / Hypercapnic blood int oarteries on the mudulla / Extracelluar pH on the medulla / Threshold PCO_2 |
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| Research Abstract |
The experments were undetaken todetanmice the site and characteristics of the repoiratiry contral chaemostnsiti ve areas in anecthetize and vagotomezxed cats. Cat was paralyzed and vetilated artifically whth air. The intergrated Phrenic nerve aceivity (PNA) was used as an touput of the central inspicatory activity. Results obtained were as follows:
1. Occusiong of the bilatreal Art. carotis externa and the Art. basiliaris inthe rostral end of the medulla suppressed markedly the PNA wchich finally disappered within onc nem. The blood perssure, which was measured in the Art. corotis exeterna down steram from the occlusion, was about 15 mm H during occlusion. Thus, the depression of the PNA would be due to an ischemia in ther upper part of the brain stem. These results indicate that the upper part of the brainstem has an intrinsic and facilitatory function for the medullay respiratory control system.
2. The respiratory responses to albolar pCO_2 were detenined during nomoxia and bypoxia (pO
… More
_2=70-40 Torr) in carotid checmdenervated cats the PNA was linerly related to alv. pCO_2 during nomoxia, and mean thresholof pCO_2 was about to Torr. Transtition from air to hypoxia led to dectrease in PNA, while alv. pCO_2 increase. The pCO_2 - PNA relationship was lenear and shifted to the right without significant significatn change in slope. The threshold pCO2 increased by about 6 Torr. These results show that the sensitivity of the central chemosentitice areas to pCO_2 is not impaired by central hypoxaemia.
3. Injection of the blood equilibrated with high C%O_2 into the anterior inferior cerebellar asteriea (AICA) caused an increase in PNA. As long as the injection of high CO_2 blood continued, an inhalation of the hypercapnis gac mexture did not produce to change in PNA and pH values of the ventral subface of the rostral medulla whsres pH values of both the caudal and intermediate artea decteased. Histological studies of the medulla after injection India inkinto the AICA showed that the vessels containing ink were obseraced exculsively in rostral medulla. These results indicate that the site of the central chemosensitive areas in the respiratory regulation system are in the rostral part of the medulla and meinly perfused by the blood bo the AICa. Less
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Research Products
(14 results)
