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AGONIST-MEDIATED AIRWAY CHALLENGE: CARDIOPULMONARY INTERACTIONS MODULATE GAS EXCHANGE AND RECOVERY
Wiester, M. J., D L. Costa, J. S. Tepper, D. W. Winsett, AND R. Slade. AGONIST-MEDIATED AIRWAY CHALLENGE: CARDIOPULMONARY INTERACTIONS MODULATE GAS EXCHANGE AND RECOVERY. RESPIRATION PHYSIOLOGY. Elsevier Science BV, Amsterdam, Netherlands, 145(2-3):183-199, (2005).
To better understand the early phase response (0-60 minutes) to airway challenge, we examined cardiopulmonary reactions during ovalbumin (OVA), histamine, and methacholine aerosol challenge tests in guinea pigs. Propranolol and 100% O2 were used to modify the reactions. Propranolol depressed blood pressure and heart rate but did not affect pulmonary function, blood gases, trapped gas, lung weight, or alter the provocative concentration of histamine. However, there was edema and more trapped gas in the lung after the challenge (histamine) in propranolol treated animals. Approximately 56% of the treated animals died from challenge while none died without propranolol, suggesting that -adrenoceptors play an important role in recovery. Using OVA challenge in100% O2, we found that an absolute shunt developed in concert with the pulmonary changes. Also, challenge-induced gasps were associated with sharp increases in arterial O2 (methacholine challenge). Results suggest that the early phase response occurs in small conducting airways resulting in an absolute shunt and hypoxemia. -adrenoceptors appear critical to recovery from this bronchoconstriction stress.
To better understand the early phase response (0-60 minutes) to airway challenge
Record Details:Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LAB
EXPERIMENTAL TOXICOLOGY DIVISION
PULMONARY TOXICOLOGY BRANCH