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Respiratory Control During Exercise: Hormones, Osmolality, Strong Ions, and Paco2
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Respiratory Control During Exercise: Hormones, Osmolality, Strong Ions, and Paco2
作者:
Donald B. Jennings,
期刊:
Canadian Journal of Applied Physiology
(NRC Available online 1994)
卷期:
Volume 19,
issue 3
页码: 334-349
ISSN:1066-7814
年代: 1994
DOI:10.1139/h94-027
出版商: NRC Research Press
关键词: circumventricular organs;central chemoreception;angiotensin II;vasopressin;alphastat theory
数据来源: NRC
摘要:
For optimal performance of exercising muscle, the charge state of proteins must be maintained; the pH environment of protein histidine imidazole groups must be coordinated with their pK. During exercise, increasing temperature and osmolality as well as changes in strong ions affect the pK of imidazole groups. Production of strong organic anions also decreases the concentration difference between strong cations and anions (strong ion difference, or [SID]), causing a metabolic acidosis in peripheral tissues. Central chemoreceptors regulatein relation to the [SID] of brain fluids to maintain a "constant" brain [H+]. In addition, increased osmolality, angiotensin II, and vasopressin during exercise may stimulate circumventricular organs of the brain and interact with chemical control of ventilation. Changes in [SID] of brain fluids during exercise are negligible compared to systemic decreases in [SID]; thus, regulation ofto maintain brain [H+] homeostasis cannot simultaneously compensate for greater changes in [SID] in peripheral tissues.Key words: circumventricular organs, central chemoreception, angiotensin II, vasopressin, alphastat theory
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