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MUSCLE VENOUS PO 2 AND V.O 2 ARE LINEARLY RELATED IN REPETITIVE TETANIC CONTRACTIONS OF CANINE MUSCLE DURING HYPOXIC HYPOXIA
Author(s) -
Kohzuki H,
Misawa H,
Kishi T,
Ohga Y,
Sakata S,
Takaki M
Publication year - 1999
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1046/j.1440-1681.1999.03100.x
Subject(s) - isometric exercise , chemistry , hypoxia (environmental) , perfusion , medicine , anatomy , gastrocnemius muscle , endocrinology , oxygen , anesthesia , skeletal muscle , organic chemistry
1. It has previously been shown that perfusion with high O 2 ‐affinity‐erythrocytes decreases venous PO 2 (PVO 2 ) and decreases O 2 uptake (V.O 2 ) in contracting muscle at the same O 2 delivery (arterial O 2 concentration × flow). A linear V.O 2 –PVO 2 relationship has been obtained with a V.O 2 ‐axis intercept, suggesting that, during this type of hypoxia, V.O 2 is composed of a PVO 2 ‐dependent and ‐independent V.O 2 . However, the V.O 2 – PVO 2 relation during hypoxic hypoxia has not been examined. 2. To clarify this relation, PVO 2 and V.O 2 have been measured in contracting gastrocnemius (1 Hz trains of 0.2 s isometric tetani) under both normoxic and hypoxic conditions during 5 min of stimulation. 3. Venous O 2 changes proportionally with O 2 delivery. Each V.O 2 –PVO 2 relation was linear, with the mean described by the equation V.O 2 = 5.06 + 0.41 × PVO 2 ( n = 6, r = 0.81, P < 0.05). The V.O 2 ‐axis intercept was significantly different from zero ( P < 0.05). 4. These results were similar to those obtained during hypoxia induced by high O 2 ‐affinity‐erythrocytes. We conclude that there is a linear relationship between PVO 2 and V.O 2 above the V.O 2 ‐axis intercept, regardless of the type of hypoxia.