TY - JOUR
T1 - Increases in arterial blood oxygen during exercise in the lemon shark (Negaprion brevirostris)
AU - Bushnell, P. G.
AU - Lutz, P. L.
AU - Steffensen, J. F.
AU - Oikari, A.
AU - Gruber, S. H.
PY - 1982/3/1
Y1 - 1982/3/1
N2 - Polyethylene cannulae were implanted in pre- and post-branchial blood vessels allowing nonstressful blood sampling over a variety of activity ranges in an active tropical elasmobranch, the lemon shark (Negaprion brevirostris). The P50 was found to be 11.8 Torr at 24°C and pH of 7.7. A Bohr shift of -0.36 was also found. Blood Po2 and oxygen content were measured during rest, routine swimming, and exercise in unanesthetized, free swimming juveniles. Under all conditions venous oxygen levels were low with venous Po2 of 7.1±2.7 Torr, and venous oxygen content ( {Mathematical expression}) of 0.56±0.4 vol%. However, a large variability was found in arterial blood measurements. Arterial Po2 ranged from 7 to 80 Torr, while arterial oxygen content (Cao2) varied from 1.6 vol% to 6.8 vol% among ten experimental animals. A significant increase in arterial Po2, oxygen content, and hematocrit was noted during increased activity. Since the venous system provides little or no oxygen reserve, increased oxygen extraction from the blood ( {Mathematical expression}) appears to be met by an increase in Cao2 rather than a decrease in {Mathematical expression}. Mechanisms to accomplish this may include increasing hematocrit and vacular gill shunts.
AB - Polyethylene cannulae were implanted in pre- and post-branchial blood vessels allowing nonstressful blood sampling over a variety of activity ranges in an active tropical elasmobranch, the lemon shark (Negaprion brevirostris). The P50 was found to be 11.8 Torr at 24°C and pH of 7.7. A Bohr shift of -0.36 was also found. Blood Po2 and oxygen content were measured during rest, routine swimming, and exercise in unanesthetized, free swimming juveniles. Under all conditions venous oxygen levels were low with venous Po2 of 7.1±2.7 Torr, and venous oxygen content ( {Mathematical expression}) of 0.56±0.4 vol%. However, a large variability was found in arterial blood measurements. Arterial Po2 ranged from 7 to 80 Torr, while arterial oxygen content (Cao2) varied from 1.6 vol% to 6.8 vol% among ten experimental animals. A significant increase in arterial Po2, oxygen content, and hematocrit was noted during increased activity. Since the venous system provides little or no oxygen reserve, increased oxygen extraction from the blood ( {Mathematical expression}) appears to be met by an increase in Cao2 rather than a decrease in {Mathematical expression}. Mechanisms to accomplish this may include increasing hematocrit and vacular gill shunts.
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U2 - 10.1007/BF00689288
DO - 10.1007/BF00689288
M3 - Article
AN - SCOPUS:0002705085
VL - 147
SP - 41
EP - 47
JO - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
JF - Journal of Comparative Physiology B: Biochemical, Systemic, and Environmental Physiology
SN - 0174-1578
IS - 1
ER -