Importance of mitochondrial PO2in maximal O2 transport and utilization: A theoretical analysis
In previous calculations of how the O2 transport system limits .VO2(max), it was reasonably assumed that mitochondrial P(O2) (Pm(O2)) could be neglected (set to zero). However, in reality, Pm(O2) must exceed zero and the red cell to mitochondrion diffusion gradient may therefore be reduced, impairin...
| Authors: | , , , , , |
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| Format: | article |
| Status: | Versión aceptada para publicación |
| Publication Date: | 2013 |
| Country: | España |
| Institution: | Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya) |
| Repository: | Recercat. Dipósit de la Recerca de Catalunya |
| OAI Identifier: | oai:recercat.cat:2445/57804 |
| Online Access: | https://hdl.handle.net/2445/57804 |
| Access Level: | Open access |
| Keyword: | Mitocondris Oxigen Transport Respiració Bioenergètica Mitochondria Oxygen Transportation Respiration Bioenergetics |
| Summary: | In previous calculations of how the O2 transport system limits .VO2(max), it was reasonably assumed that mitochondrial P(O2) (Pm(O2)) could be neglected (set to zero). However, in reality, Pm(O2) must exceed zero and the red cell to mitochondrion diffusion gradient may therefore be reduced, impairing diffusive transport of O2 and .VO2(max). Accordingly, we investigated the influence of Pm(O2) on these calculations by coupling previously used equations for O2 transport to one for mitochondrial respiration relating mitochondrial .VO2 to P(O2). This hyperbolic function, characterized by its P50 and V˙MAX, allowed Pm(O2) to become a model output (rather than set to zero as previously). Simulations using data from exercising normal subjects showed that at .VO2(max), Pm(O2) was usually <1mmHg, and that the effects on .VO2(max) were minimal. However, when O2 transport capacity exceeded mitochondrial V˙MAX, or if P50 were elevated,Pm(O2) often reached double digit values, thereby reducing the diffusion gradient and significantly decreasing .VO2(max). |
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