| Project/Area Number |
07670651
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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 |
Respiratory organ internal medicine
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| Research Institution | Tohoku University |
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Principal Investigator |
SEKIZAWA Kiyohisa Department of Geriatric Medicine Tohoku University School of Medicine Associate Professor, 医学部・附属病院, 助教授 (50171335)
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| Project Period (FY) |
1995 – 1996
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| Project Status |
Completed (Fiscal Year 1996)
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| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1996: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1995: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | Cough / Defense mechanism / Pneumonia in the elderly / Substance P / C-fiber / Copsaicin / Airway in flammation / Bronchoal asthma / 咳反射 / 誤嚥性肺炎 / ACE阻害剤 / 睡眠 / 嚥下反射 |
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| Research Abstract |
Cough is the most important symptom of respiratory disease and a decrease in cough reflex is believed to cause pneumonia. A machine continuously measuring the number of coughs during 24 hours is needed to elucidate mechanisms of cough and to control cough in patients with respiratory disease. We therefore developed the portable machine that able to count the number of coughs continuously for 24 hours and to distinguish cough from conversation. However, frictional sounds produced by interaction between a microphone and clothes had a similar power spectrum as cough sound, and therefore it was impossible to count the number of coughs. Now, we are trying to develop a new strategy for a continuous measurement of the number of coughs.
To investigate mechanisms of cough, we used awake guinea pigs for measuring the number of coughs during the treatment with phosphoramidon, an angiotensin converting enzyme inhibitor and bronchoconstriction induced by acetylcholine, histamine and ovalbumin antigen. A substance P antagonist attenuated the cough response in all cases in guinea pigs, and therefore it is suggested that substance P may be a mechanism responsible for the development of cough in the body. In humans, the levels of substance P in suputum were markedly low in patients with aspiration pneumonia who had the attenuated cough response compared to controls. These results suggest that substance P in the airway may be an important substance for causing cough and a reduction of substance P content in the airway may lead the patients to aspiration pneumonia.
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