Oxygen transport and acid-base balance during exercise in the tammar wallaby.
Rates of oxygen consumption (V(O)2), body temperatures and pulmonary blood temperatures, blood gases and blood pH were measured for seven 4.9+/-0.8 (SE) kg tammar wallabies (Macropus eugenii) during rest and during treadmill hopping. For animals resting on the treadmill V(O)2 averaged 0.030+/-0.003 L min(-1). During hopping V(O)2 increased linearly with speed up to 2.5 m sec(-1). Above 2.5 m sec(-1) V(O)2 was independent of hopping speed and averaged 0.340+/-0.004 L min(-1). At rest, rectal temperatures and pulmonary blood temperatures averaged 36 degrees C. During treadmill hopping, rectal temperatures and pulmonary blood temperatures increased similarly, to 39 degrees C. The Pv(CO)2 increased and pHv decreased in proportion to the increased V(O)2. The Pa(CO)2 and pHa were not significantly changed from values for animals resting on the treadmill. Cardiac output (Vb) averaged 0.97+/-0.04 L min(-1) when the wallabies were at rest on the treadmill and increased linearly with treadmill speeds up to 2.5 m sec(-1). Above 2.5 m sec(-1) Vb was independent of hopping speed and averaged 2.9+/-0.04 L min(-1). When data for all speeds were combined, Vb increased linearly with V(O)2. Thus, in spite of their unique mode of locomotion wallabies have maintained relationships between pulmonary ventilation and V(O)2 and between Vb and V(O)2 that are similar to those reported for eutherian mammals.
Snyder
G K
GK
Department of Biology, University of Colorado, Boulder 80309-0334, USA. snydergk@spot.colorado.edu
Baudinette
R V
RV
Gannon
B J
BJ
D000136:Acid-Base Equilibrium / Q000502:physiology*; D000818:Animals; D001784:Blood Gas Analysis; D001831:Body Temperature / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D006400:Hematocrit; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008168:Lung / Q000502:physiology; D007614:Macropodidae / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012146:Rest / Q000502:physiology; D013990:Tidal Volume / Q000502:physiology