The Role of Membrane Fluidity Changes and Thiobarbituric Acid-Reactive Substances Production in the Inhibition of Cerebral Cortex Na+/K+-ATPase Activity

H. RAUCHOVÁ, Z. DRAHOTA, J. KOUDELOVÁ¹

Institute of Physiology, Academy of Sciences of the Czech Republic and 1Institute of Physiology, First Faculty of Medicine, Charles University, Prague, Czech Republic

Received April 10, 1998
Accepted October 26, 1998

Summary
Lipid peroxidation of rat cerebral cortex membranes was induced by Fe²⁺/ADP and ascorbate. The rate of
Na⁺/K⁺-ATPase inhibition was correlated with the increase of thiobarbituric acid-reactive substances (TBARS) and conjugated dienes (CD) and with membrane fluidity changes. Our data showed that membrane fluidity changes (evaluated by fluorescence steady-state anisotropy measurements) can participate in Na⁺/K⁺-ATPase inhibition during the initial period of lipid peroxidation process, whereas during the following period the enzyme inhibition correlates only with TBARS and CD production.

Key words
Cerebral cortex membranes - Na⁺/K⁺-ATPase - Lipid peroxidation - Membrane fluidity