Oxygen Exchange Profile in Rat Muscles of Contrasting Fibre Types
- 1 June 2003
- journal article
- research article
- Published by Wiley in Journal Of Physiology-London
- Vol. 549 (2), 597-605
- https://doi.org/10.1113/jphysiol.2002.035915
Abstract
To determine whether fibre type affects the O2 exchange characteristics of skeletal muscle at the microcirculatory level we tested the hypothesis that, following the onset of contractions, muscle comprising predominately type I fibres (soleus, Sol, 86 % type I) would, based on demonstrated blood flow responses, exhibit a blunted microvascular PO2 (PO2,m, which is determined by the O2 delivery () to O2 uptake () ratio) profile (assessed via phosphorescence quenching) compared to muscle of primarily type II fibres (peroneal, Per, 84 % type II). PO2,m was measured at rest, and following the rest-contractions (twitch, 1 Hz, 2–4 V for 120 s) transition in Sol (n = 6) and Per (n = 6) muscles of Sprague-Dawley rats. Both muscles exhibited a delay followed by a mono-exponential decrease in PO2,m to the steady state. However, compared with Sol, Per demonstrated (1) a larger change in baseline minus steady state contracting PO2,m (ΔPO2,m) (Per, 13.4 ± 1.7 mmHg; Sol, 8.6 ± 0.9 mmHg, P < 0.05); (2) a faster mean response time (i.e. time delay (TD) plus time constant (τ); Per, 23.8 ± 1.5 s; Sol, 39.6 ± 4.3 s, P < 0.05); and therefore (3) a greater rate of PO2,m decline (ΔPO2,m/τ; Per, 0.92 ± 0.08 mmHg s−1; Sol, 0.42 ± 0.05 mmHg s−1, P < 0.05). These data demonstrate an increased microvascular pressure head of O2 at any given point after the initial time delay for Sol versus Per following the onset of contractions that is probably due to faster dynamics relative to those of .This publication has 60 references indexed in Scilit:
- Rat Muscle Microvascular PO2 Kinetics During the Exercise Off‐TransientExperimental Physiology, 2001
- A Comparison of the Microcirculation in the Rat Spinotrapezius and Diaphragm MusclesMicrovascular Research, 1998
- Muscle characteristics in Thoroughbreds of different ages and sexesEquine Veterinary Journal, 1991
- Central and Peripheral Aspects of Oxygen Transport and Adaptations with ExerciseSports Medicine, 1991
- A Histochemical Method for the Simultaneous Demonstration of Capillaries and Fiber Type in Skeletal MuscleStain Technology, 1987
- Myoglobin levels in individual human skeletal muscle fibers of different types.Journal of Histochemistry & Cytochemistry, 1984
- Correlated reduction of velocity of shortening and the rate of energy utilization in mouse fast-twitch muscle during a continuous tetanus.The Journal of general physiology, 1983
- Estimating length density and quantifying anisotropy in skeletal muscle capillariesJournal of Microscopy, 1983
- Metabolic Characteristics of Fibre Types in Human Skeletal MuscleActa Physiologica Scandinavica, 1975
- STEREOLOGICAL ANALYSIS OF MAMMALIAN SKELETAL MUSCLEThe Journal of cell biology, 1974