1. 1. Oxygen consumption rate and cardiovascular variables contributing to O2 transport were measured for marine toads (S. marinus) at rest and during enforced activity. 2. 2. An 8.3 fold increase in VO2 with activity was accompanied by elevation of heart rate, systemic arch blood flow, and arterial and venous blood pressures. Systemic arch pulse volume declined slightly with activity. Peripheral vascular resistance declined 40% with activity. Arterial PO2 and pco2 increased with activity, whereas pH declined. Venous pco2 increased and po2 and pH declined with activity. Consequently, the arteriovenous difference in po2 increased from 12 torr at rest to 62 torr during activity: the calculated arteriovenous difference in blood % saturation increased from 6.5 to 58%. There was a metabolic acidosis during activity. 3. 3. The % contributions of the cardiovascular variables to the VO2 increment during activity were: heart rate, +17%: systemic arch pulse volume, -2%; arteriovenous % saturation difference, +85%. 4. 4. The large contribution of arteriovenous difference is due to both elevation of arterial and decline of venous saturation. © 1988.
|Number of pages||5|
|Journal||Comparative Biochemistry and Physiology -- Part A: Physiology|
|Publication status||Published - 1988|