Redox changes in cat brain cytochrome-c oxidase after blood-fluorocarbon exchange

M. Ferrari, D. F. Hanley, D. A. Wilson, R. J. Traystman

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


Rapid scanning near-infrared spectroscopy (730-960 nm) was utilized to determine cat brain cytochrome-c oxidase copper band by blood-perfluorochemical emulsion (Oxypherol) exchange. Spectra were carried out before, during, and after the exchange transfusion on animals with preserved somatosensory-evoked potentials and microsphere-determined cerebral blood flow. Remaining hemoglobin (<4% of control) was converted to carboxyhemoglobin that does not absorb in this spectral region. Difference spectra, between an hypercapnic status (8% CO2-92% O2) and postmortem, demonstrated the presence of a broad absorption band centered around 820-845 nm that could be attributed to the oxidized low potential copper ion (Cu(A)) of cytochrome-c oxidase. However, we were unable to further oxidize this band by adding CO2 to the inspired gas mixture, but this inconsistency may be due to the near-maximal cerebral blood flow levels present in this preparation. Cytochrome oxidation by CO2 is normally attributed to increased O2 delivery to the tissue, secondary to an increased cerebral perfusion. We were unable to induce further increases in cerebral blood flow. In contrast, the cytochrome band could be reduced both by lowering fractional O2 concentration and by inducing circulatory arrest. The spectral data support the hypothesis that it is possible to quantify the cytochrome-c oxidase copper band in the near-infrared spectral region.

Original languageEnglish (US)
Pages (from-to)H1706-H1713
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Issue number6 27-6
StatePublished - 1990


  • brain oxygenation
  • cerebral blood flow
  • infrared spectroscopyo

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)


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