We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Dynamics of PO<sub>2</sub> and VO<sub>2</sub> in resting and contracting rat spinotrapezius muscle.
- Authors
Golub, Aleksander S.; Song, Bjorn K.; Nugent, William H.; Pittman, Roland N.
- Abstract
This study examined changes in interstitial PO2, which allowed calculation of VO2 during periods of rest, muscle contraction and recovery using an in situ rat spinotrapezius muscle preparation. The PO2 was measured using phosphorescence quenching microscopy and the muscle VO2 was calculated as the rate of O2 disappearance during brief periods of muscle compression to stop blood flow with a supra-systolic pressure. The PO2 and VO2 measurements were made during "5 s compression and 15 s recovery" (CR) cycles. With all three stimulation frequencies, 1, 2 and 4 Hz, the fall in interstitial PO2 and rise in VO2 fromresting values occurred within the first 20 s of contraction. The PO2 during contraction became lower as stimulation frequency increased from 1 to 4 Hz. VO2 was higher at 2 Hz than at 1 Hz contraction. With cessation of stimulation, PO2 began increasing exponentially towards baseline values. After 1 and 2 Hz contraction, the fall in muscleVO2 was delayed by oneCR cycle and then exponentially decreased towards resting values. After 4 Hz stimulation, VO2 increased for 2 cycles and then decreased. The post-contraction transients of PO2 and VO2 were not synchronous and had different time constants. With further analysis two distinct functional responses were identified across all stimulation frequencies having PO2 during contraction above or below 30 mmHg. The corresponding VO2 responses were different - for "high" PO2,muscleVO2 reachedhigh levels, while for the "low" PO2 data setmuscle VO2 remained low. Recovery patterns were similar to those described above. In summary, local microscopic PO2 and VO2 were measured in resting and contractingmuscle in situ and the post-contraction transients of PO2 and VO2 were all much slower than the onset transients.
- Subjects
MUSCLE contraction; BLOOD flow; RATS; IN situ processing (Mining); REST periods
- Publication
Frontiers in Physiology, 2023, p1
- ISSN
1664-042X
- Publication type
Article
- DOI
10.3389/fphys.2023.1172834