Advertisement
Journal Articles
Ventilatory and cardiovascular responses of a python (Python molurus) to exercise and digestion
S.M. Secor, J.W. Hicks, A.F. Bennett
Journal of Experimental Biology 2000 203: 2447-2454;

Summary

To investigate the potential limiting steps of peak metabolic rates, we examined gas exchange rates (vdot (O2), vdot (CO2)), respiratory exchange ratio (RER), breathing frequency, tidal volume, minute ventilation volume (V.e) as well as the heart rate, systemic blood flow and stroke volume of Burmese pythons (Python molurus) while fasting at rest, exercising, digesting and exercising while digesting. All measured variables increased significantly during exercise (crawling at 0.4 km h(−)(1) and at vdot (O2max)), highlighted by a 17-fold increase in vdot (CO2) and a 24-fold increase in V.e. During the digestion of a meal equivalent to 25 % of the snake's body mass, pythons responded with increases in vdot (O2) and heart rate similar to those experienced during exercise, along with a 4.5-fold increase in systemic blood flow. Interestingly, pythons hyperventilated while exercising, whereas they hypoventilated during digestion. The combined demands of exercise and digestion resulted in significantly higher vdot (O2), vdot (CO2), breathing frequency and heart rate than during either exercise or digestion alone. Evidently, the capacities of the ventilatory and cardiovascular systems to transport oxygen to locomotor muscles are not a limiting factor in the attainment of peak metabolic rates during exercise in pythons

REFERENCES

    1. Brett, J. R.
    (1972). The metabolic demand for oxygen in fish, particularily salmonids and a comparison with other vertebrates. Respir. Physiol 14, 151–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Longworth, K. E.,
    2. Jones, J. H.,
    3. Bicudo, J. E. P. W.,
    4. Taylor, C. R. and
    5. Weibel, W. R.
    (1989). High rate of O2consumption in exercising foxes: large P Odifference drives diffusion across the lung. Respir. Physiol 77, 263–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Pan, L. G.,
    2. Forster, H. V.,
    3. Bisgard, G. E.,
    4. Dorsey, S. M. and
    5. Busch, M. A.
    (1984). Cardiodynamic variables and ventilation during treadmill exercise in ponies. J. Appl. Physiol 57, 753–.
    OpenUrlAbstract/FREE Full Text
    1. Secor, S. M. and
    2. Diamond, J.
    (1995). Adaptive responses to feeding in Burmese pythons: pay before pumping. J. Exp. Biol 198, 1313–.
    OpenUrlAbstract/FREE Full Text
    1. Seeherman, H. J.,
    2. Taylor, C. R.,
    3. Maloiy, G. M. O. and
    4. Armstrong, R. B.
    (1981). Design of the mammalian respiratory system. II. Measuring maximum aerobic capacity. Respir. Physiol 44, 11–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Segal, K. R. and
    2. Gutin, B.
    (1983). Thermal effects of food and exercise in lean and obese women. Metabolism 32, 581–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Suarez, R. K.
    (1992). Hummingbird flight: Sustaining the highest mass-specific metabolic rates among vertebrates. Experientia 48, 565–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Suarez, R. K.
    (1996). Upper limits to mass-specific metabolic rates. Annu. Rev. Physiol 58, 583–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Taylor, R.,
    2. Maloiy, G. M. O.,
    3. Weibel, E. R.,
    4. Langman, V. A.,
    5. Kamau, J. M. Z.,
    6. Seeherman, H. J. and
    7. Heglund, N. C.
    (1981). Design of the mammalian respiratory system. III. Scaling maximum aerobic capacity to body mass: wild and domestic mammals. Respir. Physiol 44, 25–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Vinegar, A.,
    2. Hutchison, V. H. and
    3. Dowling, H. G.
    (1970). Metabolism, energetics and thermoregulation during brooding of snakes of the genus Python (Reptilia, Boidae). Zoologica 55, 19–.
    OpenUrl
    1. Wagner, P. D.
    (1996). Determinants of maximal oxygen transport and utilization. Annu. Rev. Physiol 58, 21–.
    OpenUrlCrossRefPubMedWeb of Science
    1. Walton, M.,
    2. Jayne, B. C. and
    3. Bennett, A. F.
    (1990). The energetic cost of limbless locomotion. Science 249, 524–.
    OpenUrlAbstract/FREE Full Text
    1. Wang, T.,
    2. Carrier, D. R. and
    3. Hicks, J. W.
    (1997). Ventilation and gas exchange in lizards during treadmill exercise. J. Exp. Biol 200, 2629–.
    OpenUrlAbstract
    1. Welle, S.
    (1984). Metabolic responses to a meal during rest and low-intensity exercise. Am. J. Clin. Nutrit 40, 990–.
    OpenUrlAbstract/FREE Full Text
Back to top

 Download PDF

Email
Journal Articles
Ventilatory and cardiovascular responses of a python (Python molurus) to exercise and digestion
S.M. Secor, J.W. Hicks, A.F. Bennett
Journal of Experimental Biology 2000 203: 2447-2454;
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
Citation Tools
Alerts

Article navigation

Other journals from The Company of Biologists

Advertisement

Welcome to JEB’s new Editor Monica Daley

We are pleased to welcome Monica Daley to JEB’s Editorial team. Monica has had a long association with JEB before taking up her new role, overseeing peer review of neuromuscular physiology, terrestrial biomechanics and integrative physiology of locomotion.

In the field with Robyn Hetem

Continuing our fieldwork series, Robyn Hetem reflects on working with species ranging from aardvark to zebra, and the impact COVID-19 has had on fieldwork.

Read & Publish participation continues to grow

“It is particularly encouraging for early career researchers, as it allows them to display their research globally without the need to find costs to cover the open access option.”

Professor Fernando Montealegre-Z (University of Lincoln) shares his experience of publishing Open Access as part of our growing Read & Publish initiative. We now have over 150 institutions in 15 countries and four library consortia taking part – find out more and view our full list of participating institutions.

Nocturnal reef residents have deep-sea-like eyes

Fanny de Busserolles and colleagues from The University of Queensland have discovered that the eyes of nocturnal reef fish have multibank retinas, layers of photoreceptors, similar to the eyes of deep-sea fish that live in dim light conditions.

Mechanisms underlying gut microbiota–host interactions in insects

In their Review, Konstantin Schmidt and Philipp Engel summarise recent findings about the mechanisms involved in gut colonisation and the provisioning of beneficial effects in gut microbiota–insect symbiosis.