|
| |
|
|
|
|
||||
| Home Help Feedback Subscriptions Archive Search Table of Contents | ||||
Journal of Experimental Biology, Vol 200, Issue 20 2629-2639, Copyright © 1997 by Company of Biologists
JOURNAL ARTICLES |
T Wang, DR Carrier and JW Hicks
Department of Ecology, University of California at Irvine, Irvine, CA 92717, USA. wang@biology.ou.dk
The extent to which lizards ventilate their lungs during locomotion is controversial. Direct measurements of airflow across the nostrils suggest a progressive reduction in tidal volume and minute ventilation with increased running speed, while other studies have demonstrated that arterial PO2 remains constant during exercise. To resolve these conflicting findings, we measured minute ventilation and gas exchange rate in five specimens of Varanus exanthematicus and five specimens of Iguana iguana during treadmill locomotion at speeds between 0.14 and 1.11ms-1 at 35 degrees C. These speeds are much lower than maximal running speeds, but are greater than the maximal aerobic speed. In both species, the ventilatory pattern during locomotion was highly irregular, indicating an interference between locomotion and lung ventilation. In Varanus exanthematicus, treadmill locomotion elicited a six- to eightfold increase in minute ventilation from a pre-exercise level of 102mlkg-1min-1, whereas the rate of oxygen uptake increased approximately threefold (from 3.9 to 12.6mlkg-1min-1). After exercise, both minute ventilation and gas exchange rate decreased immediately. Because minute ventilation increased more than did oxygen consumption, an increase in lung PO2 during exercise is predicted and, thus, Varanus exanthematicus appears effectively to ventilate its lungs to match the increased metabolic rate during locomotion at moderate speed. In Iguana iguana, both minute ventilation and gas exchange rate increased above resting values during locomotion at 0.28ms-1, but both decreased with further increases in locomotor speed. Furthermore, following exercise, both minute ventilation and oxygen uptake rate increased significantly. Iguana iguana, therefore, appears to be unable to match the increased oxygen demand with adequate ventilation at moderate and higher speeds.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
This article has been cited by other articles:
|
|
 |
|
  G. L. J. Galli, D. E. Warren, and H. A. Shiels Ca2+ cycling in cardiomyocytes from a high-performance reptile, the varanid lizard (Varanus exanthematicus) Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2009; 297(6): R1636 - R1644. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. R. Donovan and T. T. Gleeson Scaling the duration of activity relative to body mass results in similar locomotor performance and metabolic costs in lizards J. Exp. Biol., October 15, 2008; 211(20): 3258 - 3265. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. L. J. Galli, H. Gesser, E. W. Taylor, H. A. Shiels, and T. Wang The role of the sarcoplasmic reticulum in the generation of high heart rates and blood pressures in reptiles J. Exp. Biol., May 15, 2006; 209(10): 1956 - 1963. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. K. Hartzler, S. L. Munns, A. F. Bennett, and J. W. Hicks Metabolic and blood gas dependence on digestive state in the Savannah monitor lizard Varanus exanthematicus: an assessment of the alkaline tide J. Exp. Biol., March 15, 2006; 209(6): 1052 - 1057. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Skals, N. Skovgaard, A. S. Abe, and T. Wang Venous tone and cardiac function in the South American rattlesnake Crotalus durissus: mean circulatory filling pressure during adrenergic stimulation in anaesthetised and fully recovered animals J. Exp. Biol., October 1, 2005; 208(19): 3747 - 3759. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. L. Munns, L. K. Hartzler, A. F. Bennett, and J. W. Hicks Terrestrial locomotion does not constrain venous return in the American alligator, Alligator mississippiensis J. Exp. Biol., September 1, 2005; 208(17): 3331 - 3339. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. L. Munns, L. K. Hartzler, A. F. Bennett, and J. W. Hicks Elevated intra-abdominal pressure limits venous return during exercise in Varanus exanthematicus J. Exp. Biol., November 1, 2004; 207(23): 4111 - 4120. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Landberg, J. D. Mailhot, and E. L. Brainerd Lung ventilation during treadmill locomotion in a terrestrial turtle, Terrapene carolina J. Exp. Biol., October 1, 2003; 206(19): 3391 - 3404. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Klein, D. V. Andrade, A. S. Abe, and S. F. Perry Role of the post-hepatic septum on breathing during locomotion in Tupinambis merianae (Reptilia: Teiidae) J. Exp. Biol., July 1, 2003; 206(13): 2135 - 2143. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Frappell, T. Schultz, and K. Christian Oxygen transfer during aerobic exercise in a varanid lizard Varanus mertensi is limited by the circulation J. Exp. Biol., September 1, 2002; 205(17): 2725 - 2736. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. M. Deban and D. R. Carrier Hypaxial muscle activity during running and breathing in dogs J. Exp. Biol., July 1, 2002; 205(13): 1953 - 1967. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Wang, E. W. Taylor, D. Andrade, and A. S. Abe Autonomic control of heart rate during forced activity and digestion in the snake Boa constrictor J. Exp. Biol., March 12, 2002; 204(20): 3553 - 3560. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. M. Fife, C. L. Bailey, D. V. Lee, and D. R. Carrier Function of the oblique hypaxial muscles in trotting dogs J. Exp. Biol., January 7, 2001; 204(13): 2371 - 2381. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. R. Carrier and C. G. Farmer The Integration of Ventilation and Locomotion in Archosaurs Integr. Comp. Biol., February 1, 2000; 40(1): 87 - 100. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Farmer and J. Hicks Circulatory impairment induced by exercise in the lizard Iguana iguana J. Exp. Biol., January 9, 2000; 203(17): 2691 - 2697. [Abstract] [PDF]
|
|
|
|
|
|
J. Hicks, T Wang, and A. Bennett Patterns of cardiovascular and ventilatory response to elevated metabolic states in the lizard Varanus exanthematicus J. Exp. Biol., January 8, 2000; 203(16): 2437 - 2445. [Abstract] [PDF]
|
|
|
|
|
|
S. Secor, J. Hicks, and A. Bennett Ventilatory and cardiovascular responses of a python (Python molurus) to exercise and digestion J. Exp. Biol., January 8, 2000; 203(16): 2447 - 2454. [Abstract] [PDF]
|
|
|
|
|
|
C. Farmer and D. Carrier Ventilation and gas exchange during treadmill locomotion in the American alligator (Alligator mississippiensis) J. Exp. Biol., January 6, 2000; 203(11): 1671 - 1678. [Abstract] [PDF]
|
|
|
|
|
|
C. Farmer and D. Carrier Pelvic aspiration in the American alligator (Alligator mississippiensis) J. Exp. Biol., January 6, 2000; 203(11): 1679 - 1687. [Abstract] [PDF]
|
|
|
|
 |
|
 T. Owerkowicz, C. G. Farmer, J. W. Hicks, and E. L. Brainerd Contribution of Gular Pumping to Lung Ventilation in Monitor Lizards Science, June 4, 1999; 284(5420): 1661 - 1663. [Abstract] [Full Text]
|
|
