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Ventilatory long-term facilitation in unanesthetized rats. J Appl Physiol (1985) 2001 Aug;91(2):709-16 PMID: 11457785

Pubmed ID



We tested the hypothesis that unanesthetized rats exhibit ventilatory long-term facilitation (LTF) after intermittent, but not continuous, hypoxia. Minute ventilation (VE) and carbon dioxide production (VCO(2)) were measured in unanesthetized, unrestrained male Sprague-Dawley rats via barometric plethysmography before, during, and after exposure to continuous or intermittent hypoxia. Hypoxia was either isocapnic [inspired O(2) fraction (FI(O(2))) = 0.08--0.09 and inspired CO(2) fraction (FI(CO(2))) = 0.04] or poikilocapnic (FI(O(2)) = 0.11 and FI(CO(2)) = 0.00). Sixty minutes after intermittent hypoxia, VE or VE/VCO(2) was significantly greater than baseline in both isocapnic and poikilocapnic conditions. In contrast, 60 min after continuous hypoxia, VE and VE/VCO(2) were not significantly different from baseline values. These data demonstrate ventilatory LTF after intermittent hypoxia in unanesthetized rats. Ventilatory LTF appeared similar in its magnitude (after accounting for CO(2) feedback), time course, and dependence on intermittent hypoxia to phrenic LTF previously observed in anesthetized, vagotomized, paralyzed rats.

Author List

Olson EB Jr, Bohne CJ, Dwinell MR, Podolsky A, Vidruk EH, Fuller DD, Powell FL, Mitchel GS


Melinda R. Dwinell PhD Center Associate Director, Associate Professor in the Physiology department at Medical College of Wisconsin


2-s2.0-0034923789   112 Citations

MESH terms used to index this publication - Major topics in bold

Carbon Dioxide
Partial Pressure
Rats, Sprague-Dawley
Respiratory Mechanics
Tidal Volume
Time Factors
jenkins-FCD Prod-332 f92a19b0ec5e8e1eff783fac390ec127e367c2b5