De Andrade, D. V.Abe, Augusto Shinya [UNESP]2014-02-262014-05-202014-02-262014-05-201999-12-01Journal of Experimental Biology. Cambridge: Company of Biologists Ltd, v. 202, n. 24, p. 3677-3685, 1999.0022-0949http://hdl.handle.net/11449/21033The tegu lizard Tupinambis merianae exhibits an episodic ventilatory pattern when dormant at 17 degrees C but a uniform ventilatory pattern when dormant at 25 degrees C. At 17 degrees C, ventilatory episodes were composed of 1-22 breaths interspaced by non-ventilatory periods lasting 1.8-26min, Dormancy at the higher body temperature was accompanied by higher rates of O-2 consumption and ventilation. The increase in ventilation was due only to increases in breathing frequency with no change observed in tidal volume. The air convection requirement for O-2 did not differ at the two body temperatures. The respiratory quotient was 0.8 at 17 degrees C and 1.0 at 25 degrees C. We found no consistent relationship between expired gas composition and the start/end of the ventilatory period during episodic breathing at 17 degrees C. However, following non-ventilatory periods of increasing duration, there was an increase in the pulmonary O-2 extraction that was not coupled to an equivalent increase in elimination of CO2 from the lungs. None of the changes in the variables studied could alone explain the initiation/termination of episodic ventilation in the tegus, suggesting that breathing episodes are shaped by a complex interaction between many variables. The estimated oxidative cost of breathing in dormant tegus at 17 degrees C was equivalent to 52.3% of the total metabolic rate, indicating that breathing is the most costly activity during dormancy.3677-3685enggas exchangeventilationbreathing patternmetabolic ratecost of breathingdormancytegu lizardTupinambis merianaeArtigoWOS:000084783000019Acesso restrito8776757457144680