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The action of carbon dioxide on constricted airways
Author(s) -
Astin T. W.,
Barer Gwenda R.,
Shaw J. W.,
Warren Patricia M.
Publication year - 1973
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1973.sp010407
Subject(s) - bronchoconstriction , acetylcholine , cats , histamine , anesthesia , pulmonary compliance , airway resistance , medicine , bronchodilator , ventilation (architecture) , lung , asthma , airway , mechanical engineering , engineering
1. In artificially ventilated open‐chest cats and dogs ventilation with 5–15% CO 2 reversed the bronchoconstriction caused by drugs or by pulmonary artery occlusion. Total lung resistance, ‘static’ lung compliance, and intratracheal or intrabronchial pressure at constant pump stroke were measured. 2. CO 2 reduced resistance and increased compliance of the lung during infusions of 5‐hydroxytryptamine (5‐HT), histamine and acetylcholine in cats. In dogs CO 2 reduced resistance during 5‐HT infusions; it caused small reductions in intratracheal pressure but no significant change in resistance during infusions of histamine and acetylcholine. Even in cats CO 2 had a larger effect during 5‐HT than during histamine and acetylcholine infusions. 3. Occlusion of a pulmonary artery caused increases in resistance and decreases in compliance in the affected lobes of both cats and dogs. These changes were partly reversed by ventilation with high CO 2 mixtures. 4. The bronchodilator action of CO 2 took place over a wide range of P a, CO2 values (20–100 torr).