Direct involvement of the glucose and Mg2⁺-ATP in the regulation of the GABAₐ-coupled Cl⁻HCO₃⁻-activated Mg2⁺-ATPase of the plasma membrane from rat brain in vitro experiences

Abstract

Effect of the glucose and Mg2+-ATP on the coupled with GABAA-receptor Cl−,HCO3−-activated Mg2+-ATPase of the plasma membranes from rat brain involving from «basal» Mg2+-ATPase which it is activated by Cl−,HCO3− ions it was investigated. The glucose (1—10 mM) decreased the «basal» Mg2+-ATPase activity on 17% and completely eliminated the enzyme activation by 10 mM Cl− +2 mM HCO3− ions. The variety effect of the glucose and Mg2+-ATP on the activation of the «basal» Mg2+-ATPase by variety concentrations of anions it was established. So it was found that in the presence Mg2+-ATP in the incubation medium >1 mM the enzyme activation by 10 mM Cl− + 2 mM HCO3− ions not appear. However, in the presence of the glucose (10 mM) the inhibiting effect of the Mg2+-ATP on the enzyme is disappears and Cl-,HCO3−-ATPase activity is restored. While, in the presence of the high concentrations 40 mM Cl− + 8 mM HCO3− in the incubation medium the inhibiting effect of the glucose and Mg2+-ATP it was negligible (~20%). It was conclusion about direct involvement of the glucose and Mg2+-ATP in the regulation of the coupled with GABAA-receptor Cl−-,HCO3−-ATPase activity of the neuronal membrane under different concentration anions in the incubation medium.