Quantification of myoglobin deoxygenation and intracellular partial pressure of O2 during muscle contraction during haemoglobin-free medium perfusion

Hisashi Takakura, Kazumi Masuda, Takeshi Hashimoto, Satoshi Iwase, Thomas Jue

Research output: Contribution to journalArticle

19 Scopus citations

Abstract

Although the O2 gradient regulates O2 flux from the capillary into the myocyte to meet the energy demands of contracting muscle, intracellular O2 dynamics during muscle contraction remain unclear. Our hindlimb perfusion model allows the determination of intracellular myoglobin (Mb) saturation () and intracellular oxygen tension of myoglobin () in contracting muscle using near infrared spectroscopy (NIRS). The hindlimb of male Wistar rats was perfused from the abdominal aorta with a well-oxygenated haemoglobin-free Krebs-Henseleit buffer. The deoxygenated Mb (Δ[deoxy-Mb]) signal was monitored by NIRS. Based on the value of Δ[deoxy-Mb], and were calculated, and the time course was evaluated by an exponential function model. Both and started to decrease immediately after the onset of contraction. The steady-state values of and progressively decreased with relative work intensity or muscle oxygen consumption. At the maximal twitch rate, and were 49% and 2.4 mmHg, respectively. Moreover, the rate of release of O2 from Mb at the onset of contraction increased with muscle oxygen consumption. These results suggest that at the onset of muscle contraction, Mb supplies O2 during the steep decline in, which expands the O2 gradient to increase the O2 flux to meet the increased energy demands.

Original languageEnglish (US)
Pages (from-to)630-640
Number of pages11
JournalExperimental Physiology
Volume95
Issue number5
DOIs
StatePublished - May 2010

ASJC Scopus subject areas

  • Physiology

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