| Effect of plasma carbonic anhydrase on ventilation in exercising dogs. | |
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MedLine Citation:
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PMID: 6777349 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Recent studies suggest pH sampled by arterial chemoreceptors may not equal that sampled by external pH electrodes, because the uncatalyzed hydration of CO2 in plasma is a slow reaction (t 1/2 approximately 9 S). The importance of this reaction rate to ventilatory control (particularly during exercise) is not known. We studied the effect of catalyzing the CO2-pH reaction in three awake exercising dogs with chronic tracheostomies and carotid loops; the dogs were trained to run on a treadmill. Respiration frequency, tidal volume, total ventilation, and end-tidal partial pressure of CO2 (PCO2) were continuously monitored. Periodically, carotid artery blood was drawn and analyzed for partial pressure of O2 (PO2), PCO2, pH, and plasma carbonic anhydrase (CA) activity. Measurements were made during steady-state exercise (3 mph and 10% grade), during a control period, after injection of a 5 ml bolus of saline, and after injection of 5 mg/kg of bovine CA dissolved in 5 ml of saline. This dose of CA increased the reaction rate by more than 80-fold. Neither the control nor the CA injections significantly altered the ventilatory parameters. Saline and CA date differed by less than 5% in ventilation, 1 Torr in arterial PCO2, 0.01 in pH units, and 1.5 Torr in end-tidal PCO2. Thus the of CO2 hydration in plasma is not a significant factor in ventilatory control. |
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Authors:
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S M Lewis; E P Hill |
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Publication Detail:
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Type: Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Journal of applied physiology: respiratory, environmental and exercise physiology Volume: 49 ISSN: 0161-7567 ISO Abbreviation: J Appl Physiol Publication Date: 1980 Oct |
Date Detail:
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Created Date: 1981-02-24 Completed Date: 1981-02-24 Revised Date: 2008-11-21 |
Medline Journal Info:
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Nlm Unique ID: 7801242 Medline TA: J Appl Physiol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 708-14 Citation Subset: IM; S |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Carbon Dioxide / blood Carbonic Anhydrases / blood, pharmacology* Dogs Dose-Response Relationship, Drug Lung / physiology Oxygen / blood Physical Exertion* Respiration / drug effects* |
| Grant Support | |
ID/Acronym/Agency:
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GM-23732/GM/NIGMS NIH HHS; HL-21990/HL/NHLBI NIH HHS; NL-16390//PHS HHS |
| Chemical | |
Reg. No./Substance:
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124-38-9/Carbon Dioxide; 7782-44-7/Oxygen; EC 4.2.1.1/Carbonic Anhydrases |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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