Effects of ethanol on ouabain inhibition of mouse brain (Na+,K+)ATPase activity》.pdfVIP

Biochemical Pharmacology, Vol. 36. No. 12, pp. 2027-2033, 1987 0006-2952/87 $3.00 + 0.00 Printed in Great Britain. Pergamon Journals Ltd. EFFECTS OF ETHANOL ON OUABAIN INHIBITION OF MOUSE BRAIN (Na+,K+)ATPase ACTIVITY PATSONT. NHAMBURO,*tS BERNARD P. SALAFSKY,*BORIS TABAKoFFt and PAULA L. I-IoFFMANt * University of Illinois, College of Medicine at Rockford, Rockford, IL 61107; and t Laboratory of Physiologic and Pharmacologic Studies, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD 20892, U.S.A. (Received 25 July 1986; accepted 25 November 1986) Abstract-Plots of ouabain inhibition of mouse cerebral cortical (Na+,K+)ATPase activity fitted a two- site model significantly better than a one-site model, consistent with the presence of two forms of the enzyme with different affinities for ouabain. The fraction of enzyme activity with high affinity for ouabain (HAO: Ki = 500 nM), suggested to be localized neuronally, constituted the major portion (60-70%) of activity. Ouabain inhibition of both components of enzyme activity was reduced as KC1 concentrations were increased. In vitro, only high concentrations of ethanol affected (Na+,K+)ATPase activity and o