Carbon monoxide-cytochrome interactions in the brain of the fluorocarbon-perfused rat.
Reflectance spectrophotometry through the skull was used to investigate carbon monoxide (CO) binding by tissue hemoproteins in the brains of barbiturate-anesthetized Sprague-Dawley rats. After splenectomy and extensive perfluorotributylamine exchange transfusion, steady-state spectral scans were obtained in Soret and visible wave-length regions during O2 ventilation, during subsequent exposure to O2-enriched gases containing 1, 3, or 5% CO, and finally after N2 anoxia. These CO exposures were well-tolerated and electroencephalograph (EEG) activity continued to be present. Initial difference spectra were influenced by CO binding to residual hemoglobin, but spectral evidence of CO-mediated b-type cytochrome reduction was obtained in the visible region as CO concentration was increased to 3 or 5%. This was associated with Soret spectra compatible with formation of the reduced cytochrome a3-CO complex. Reduction of cytochrome a at 605 nm and cytochrome c + c1 at 550 nm was absent. These findings may indicate respiratory chain branching through b cytochromes, either to a separate a3-like oxidase independent of the classical cytochrome aa3 or to an unidentified alternative CO-sensitive oxidase.
Piantadosi
C A
CA
Sylvia
A L
AL
Saltzman
H A
HA
Jöbsis-Vandervliet
F F
FF
D000818:Animals; D001802:Blood Substitutes; D001921:Brain / Q000378:metabolism*; D002248:Carbon Monoxide / Q000378:metabolism*; D002249:Carbon Monoxide Poisoning / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D003580:Cytochromes / Q000378:metabolism*; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000378:metabolism; D005466:Fluorocarbons; D006454:Hemoglobins / Q000378:metabolism; D008297:Male; D010084:Oxidation-Reduction; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D013053:Spectrophotometry
D001802:Blood Substitutes; D003574:Cytochrome c Group; D003580:Cytochromes; D005466:Fluorocarbons; D006454:Hemoglobins; C008807:perfluorotributylamine; D002248:Carbon Monoxide; D003576:Electron Transport Complex IV