Elevated intra-abdominal pressure limits venous return during exercise inVaranus exanthematicus
| Autor: | James W. Hicks, Suzanne L. Munns, Lynn K. Hartzler, Albert F. Bennett |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Mean arterial pressure
Physiology Physical Exertion Hemodynamics Blood Pressure Aquatic Science Biology Cardiovascular Physiological Phenomena Oxygen Consumption Abdomen medicine Animals Vein Molecular Biology Ecology Evolution Behavior and Systematics Tidal volume Central venous pressure Lizards Blood pressure medicine.anatomical_structure Venous Insufficiency Regional Blood Flow Insect Science Anesthesia Animal Science and Zoology Lung Volume Measurements Pulmonary Ventilation Respiratory minute volume Venous return curve |
| Zdroj: | Journal of Experimental Biology. 207:4111-4120 |
| ISSN: | 1477-9145 0022-0949 |
| DOI: | 10.1242/jeb.01279 |
| Popis: | SUMMARYThe effects of treadmill exercise on components of the cardiovascular(venous return, heart rate, arterial blood pressure) and respiratory systems(minute ventilation, tidal volume, breathing frequency, oxygen consumption,carbon dioxide production) and intra-abdominal pressure were investigated in the Savannah monitor lizard, Varanus exanthematicus B., at 35°C. Compared with resting conditions, treadmill exercise significantly increased lung ventilation, gular pumping, intra-abdominal pressure, mean arterial blood pressure and venous return (blood flow in the post caval vein). However,venous return declines at high levels of activity, and mean arterial pressure and venous return did not attain peak values until the recovery period,immediately following activity. Elevating intra-abdominal pressure in resting lizards (via saline infusion) resulted in significant reductions in venous return when the transmural pressure of the post caval vein became negative (i.e. when intra-abdominal pressure exceeded central venous pressure). Together these results suggest that increments in intra-abdominal pressure compress the large abdominal veins and inhibit venous return. During locomotion, the physical compression of the large abdominal veins may represent a significant limitation to cardiac output and maximal oxygen consumption in lizards. |
| Databáze: | OpenAIRE |
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