Modulation of mouse cerebral Na+,K(+)-ATPase activity by oxygen free radicals.
There is increasing evidence that oxygen free radicals (OFR) are involved in cerebral ischaemia-reperfusion injury, possibly via a modulation of Na+,K(+)-ATPase activity, one of the major membrane pumps responsible for ionic homeostasis. We measured OFR-mediated modulation of this enzymatic activity and examined the roles of lipid and/or protein alterations. Using mouse brain microsomes exposed to UV-C irradiation, our results show a good correlation between activity inhibition and lipoperoxidation estimated by PUFA loss as well as malondialdehyde production. The protective effect of thiourea (OH scavenger) and the lack of effect noted with DTT (thiol protector) suggest that the functionality of the Na+,K(+)-ATPase is altered by perturbation of membrane integrity rather than by a structural alteration of the protein itself.
Jamme
I
I
Laboratoire de Neurosciences, Université de Caen, France.
Petit
E
E
Divoux
D
D
Gerbi
A
A
Maixent
J M
JM
Nouvelot
A
A
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects / Q000648:ultrastructure; D004229:Dithiothreitol / Q000494:pharmacology; D016166:Free Radical Scavengers / Q000494:pharmacology; D005609:Free Radicals; D015227:Lipid Peroxidation / Q000187:drug effects; D008297:Male; D051379:Mice; D008861:Microsomes / Q000187:drug effects / Q000201:enzymology* / Q000528:radiation effects; D009419:Nerve Tissue Proteins / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013890:Thiourea / Q000494:pharmacology; D014466:Ultraviolet Rays
D016166:Free Radical Scavengers; D005609:Free Radicals; D009419:Nerve Tissue Proteins; D018696:Neuroprotective Agents; D017382:Reactive Oxygen Species; D000255:Adenosine Triphosphate; D000254:Sodium-Potassium-Exchanging ATPase; D013890:Thiourea; D004229:Dithiothreitol