Abstract
The increase in pulmonary ventilation (V̇E) during the first minutes of hypoxia is not sustained as after several minutes V̇E decreases or 'rolls-off' toward control levels. We hypothesized that intravenous infusion of theophylline, by blocking the central inhibitory effects on breathing of adenosine, would attenuate the hypoxic V̇E roll-off. Twelve unanesthetized adult goats were exposed for 20 min to a 12% O2-88% N2 gas mixture. In some studies, theophylline was infused intravenously (IV) for 20 min before and during the hypoxia. The highest infusion rate of 6.0-8.0 mg/min was sufficient to totally prevent the arterial hypertension and bradycardia that occurred with IV infusion of 4 mg · min-1 of adenosine. Nine of the 12 goats demonstrated ire roll-off without the theophylline infusion. In goats that demonstrated V̇E roll-off without theophylline, a significant (P < 0.05) V̇E roll-off was observed even at the highest theophylline infusion rate. We therefore conclude that the ire roll-off during hypoxia is not primarily or critically mediated by adenosine in awake, adult goats.
Original language | English (US) |
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Pages (from-to) | 157-164 |
Number of pages | 8 |
Journal | Respiration Physiology |
Volume | 103 |
Issue number | 2 |
DOIs | |
State | Published - Feb 1996 |
Externally published | Yes |
Bibliographical note
Funding Information:This work was supported by an American Lung Association Pediatric Pulmonary Fellowship Training Grant (W.M.G.), by U.S. Public Health Service Grant 25739, the Veterans Administration, and by the Wisconsin Sudden Infant Death Research Fund.
Copyright:
Copyright 2017 Elsevier B.V., All rights reserved.
Keywords
- Adenosine
- Control of breathing, hypoxia
- Goat
- Hypoxia
- Mammals
- Pharmacological agents
- Roll-off
- Theophylline