|Agonist-mediated airway challenge: cardiopulmonary interactions modulate gas exchange and recovery.|
|PMID: 15705534 Owner: NLM Status: MEDLINE|
|Diverse agonists used for airway challenges produce a stereotypic sequence of immediate functional responses (e.g., bronchoconstriction, gas trapping, hypoxemia, etc.) at the time such reactions are triggered. The reaction incorporates both pulmonary and cardiac changes that clearly interact in an orchestrated fashion taking the subject (or animal model) through the response generally to ultimate recovery. We hypothesize that despite differences in the initiation of the response, diverse airway provocations lead to a cascade of events that converge through a common physiologic pathway. To better understand the sequence of events and the counterbalanced cardiopulmonary responses, we examined histamine, methacholine, and ovalbumin (OVA) challenges in the awake guinea pig model and assessed ventilatory and breathing mechanics in the context of associated cardiac parameters. With the histamine response as the prototype, we evaluated the role of beta-adrenoreceptors using propranolol (1.0-10 mg/kg i.p.) and found that beta-adrenoreceptors are critical in reducing challenge-induced gas trapping in the lungs. The disposition of the circulatory response to agonist challenge (the OVA model) was reflected in a significant absolute shunting of blood through poorly ventilated regions of the lung. The methacholine challenge revealed that gasping enhanced lung inflation and reversed the diminished Pa(O2). Moreover, beta-sympathetic function was critical to recovery. Collectively, the response profiles of these disparate models of airway challenge suggest a highly integrated balance to maintain gas exchange among the pulmonary airways and vasculature, modulated in recovery by beta-adrenoreceptors.|
|Mildred J Wiester; Daniel L Costa; Jeffery S Tepper; Darrell W Winsett; Ralph Slade|
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|Type: Comparative Study; Journal Article|
|Title: Respiratory physiology & neurobiology Volume: 145 ISSN: 1569-9048 ISO Abbreviation: Respir Physiol Neurobiol Publication Date: 2005 Feb|
|Created Date: 2005-02-11 Completed Date: 2005-05-02 Revised Date: 2007-11-15|
Medline Journal Info:
|Nlm Unique ID: 101140022 Medline TA: Respir Physiol Neurobiol Country: Netherlands|
|Languages: eng Pagination: 183-99 Citation Subset: IM|
|Experimental Toxicology Division, National Health and Environmental Effects Research Laboratory, Office of Research Development, U.S. Environmental Protection Agency, B 143-01 Research Triangle Park, NC 27711, USA.|
|APA/MLA Format Download EndNote Download BibTex|
Aerosols / pharmacology
Airway Resistance / drug effects*
Anoxia / metabolism, physiopathology
Blood Pressure / drug effects
Bronchoconstriction / drug effects
Cardiovascular System / drug effects*
Dose-Response Relationship, Drug
Heart Rate / drug effects
Histamine / pharmacology
Methacholine Chloride / pharmacology*
Muscarinic Agonists / pharmacology*
Ovalbumin / pharmacology
Oxygen / metabolism
Plethysmography / methods
Propranolol / pharmacology
Pulmonary Gas Exchange / drug effects*
Reaction Time / drug effects
Respiratory Mechanics / drug effects, physiology
Respiratory System / drug effects*
Tidal Volume / drug effects
|0/Adrenergic beta-Antagonists; 0/Aerosols; 0/Muscarinic Agonists; 51-45-6/Histamine; 525-66-6/Propranolol; 62-51-1/Methacholine Chloride; 7782-44-7/Oxygen; 9006-59-1/Ovalbumin|
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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