Carbon Dioxide Concentration Alters the Dynamics of Oxygen-Mediated Capillary Blood Flow Responses in Skeletal Muscle.
A, F., GM, R.M., & GM, F. (2026). Carbon Dioxide Concentration Alters the Dynamics of Oxygen-Mediated Capillary Blood Flow Responses in Skeletal Muscle.. Microcirculation (New York, N.Y. : 1994). https://doi.org/10.1111/micc.70075
A F, GM RM, GM F. Carbon Dioxide Concentration Alters the Dynamics of Oxygen-Mediated Capillary Blood Flow Responses in Skeletal Muscle.. Microcirculation (New York, N.Y. : 1994). 2026; doi: 10.1111/micc.70075
A F, GM RM, GM F. Carbon Dioxide Concentration Alters the Dynamics of Oxygen-Mediated Capillary Blood Flow Responses in Skeletal Muscle.[J]. Microcirculation (New York, N.Y. : 1994). 2026. DOI: 10.1111/micc.70075.
@article{a2026,
author = {Folkins A and Russell McEvoy GM and Fraser GM},
title = {Carbon Dioxide Concentration Alters the Dynamics of Oxygen-Mediated Capillary Blood Flow Responses in Skeletal Muscle.},
journal = {Microcirculation (New York, N.Y. : 1994)},
year = {2026},
doi = {10.1111/micc.70075},
note = {PMID: 42365669},
}
TY - JOUR AU - Folkins A AU - Russell McEvoy GM AU - Fraser GM TI - Carbon Dioxide Concentration Alters the Dynamics of Oxygen-Mediated Capillary Blood Flow Responses in Skeletal Muscle. T2 - Microcirculation (New York, N.Y. : 1994) PY - 2026 DO - 10.1111/micc.70075 AN - PMID:42365669 ER -
HYPOTHESIS: We hypothesize that the dynamics of O2-mediated blood flow responses in skeletal muscle capillaries are altered under different tissue carbon dioxide concentrations ([CO2]) due to the interaction of overlapping mechanisms. METHODS: Eight male Sprague Dawley rats (164-215 g) were anesthetized and instrumented for systemic monitoring. The extensor digitorum longus muscle was isolated and reflected over a microfluidic gas exchange chamber mounted in an inverted microscope stage. 4-min intravital video recordings of capillary blood flow during O2 challenges consisted of a 1-min baseline at 7% O2 concentration ([O2]), followed by 3 min at 2% [O2], under constant background [CO2] at 2%, 5%, and 8%. Recordings were analyzed offline using custom MATLAB software. Time transients (τ) of capillary hemodynamic responses were determined using a least squared regression fit to single- and double-exponential models. RESULTS: Fast component τ of the O2-mediated capillary red blood cell (RBC) velocity response was 2.1 s for 2% [CO2], 3.8 s for 5% [CO2], and 7.0 s for 8% [CO2]. Third minute low [O2] capillary RBC supply rate increases from baseline were greater for 8% [CO2] (5% [CO2]: 6.4 ± 8.7 cells/s vs. 8% [CO2]: 8.5 ± 10.7 cells/s, p = 0.0007). CONCLUSION: The fast component τ of O2-mediated capillary hemodynamic responses was found to be slower with increasing background tissue [CO2], suggesting that multiple interacting mechanisms are involved to appropriately regulate O2 delivery under different CO2 conditions in partial support of the hypothesis.