These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: High affinity of blood for oxygen reduces oxygen uptake in contracting canine gracilis muscle.
    Author: Kohzuki H, Enoki Y, Sakata S, Shimizu S, Ohga Y.
    Journal: Exp Physiol; 1994 Jan; 79(1):71-80. PubMed ID: 8011318.
    Abstract:
    To clarify the influence of blood flow with high-oxygen (O2)-affinity blood on oxygen consumption (VO2) in submaximally exercising skeletal muscle, we perfused the isolated dog gracilis (n = 8) contracting under 1 Hz stimulation alternatively with normal and high-O2-affinity blood, with a constant arterial O2 content (Ca,O2) and varying perfusion rates. The average P50 (oxygen partial pressure (PO2) for half-saturation at pH 7.40, PCO2 of 40 mmHg at 37 degrees C) of the high-O2-affinity blood prepared by carbamylation was 15.5 mmHg, and that of the normal blood 33.7 mmHg. With normal blood perfusion, the average VO2 above 6 ml min-1 (100 g)-1 of O2 delivery (Ca,O2 x flow) was 4.38 ml min-1 (100 g)-1 (range 4.17-4.68 ml min-1 (100 g)-1, and VO2 at the O2 delivery range of 6-5 and 4-2.5 ml min-1 (100 g)-1 decreased to 3.96 and 2.43 ml min-1 (100 g)-1, respectively. The PO2 of venous effluent (Pv,O2) at the O2 delivery of 6 ml min-1 (100 g)-1 was 33 mmHg. With low-P50 blood perfusion, VO2 was significantly less than with normal blood, both below the O2 delivery level of 6 ml min-1 (100 g)-1 and above it, even in the fairly high O2 delivery range of 8.5-12 ml min-1 (100 g)-1 (P < 0.05). Thus, high blood flow did not compensate for the reduced VO2 caused by high-O2-affinity blood. At values of Pv,O2 less than 33 mmHg, VO2 with low-P50 blood was not significantly different from that with normal blood (P > 0.05). The reduced VO2 in submaximally exercising skeletal muscle might be due to a slower O2 dissociation from the high-O2-affinity red cells and to a limited O2 diffusion resulting from the lower Pv,O2 value (which reflects mean end-capillary PO2).
    [Abstract] [Full Text] [Related] [New Search]