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 GABA_A-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 GABA_A-receptor Cl⁻-,HCO₃⁻-ATPase activity of the neuronal membrane under different concentration anions in the incubation medium.