Vaalavirta L, Tähti H
School of Medicine, University of Tampere, Finland.
Life Sci. 1995;57(24):2223-30. doi: 10.1016/0024-3205(95)02214-4.
Astrocytes serve to maintain the proper homeostatic environment for neurons. In these regulations, the astrocyte membrane ATPase plays an important role. In the present study, the astrocyte were cultured in the modified Minimum Essential Medium (MEM), and the isolated cell membranes were exposed to solvents at different concentrations (3, 6 and 9 mM) for one hour. The activities of the membrane-bound Na+, K(+)-ATPase and Mg(2+)-ATPase were determined after exposure to aromatic, alicyclic and aliphatic hydrocarbons. Aromatic hydrocarbons decreased the enzyme activities dose-dependently according to their lipid solubilities. The slight enzyme-inhibiting effect of aliphatic and alicyclic hydrocarbons was not dependent on the lipophilicity of these solvents. Their molecular structure may have determined the solvent impact. In the present study, the activity of ouabain sensitive Na+, K(+)-ATPase in astrocytes was only 20-15% of the total ATPase activity, and in neurons 45-55%. The enzyme inhibition caused by organic solvents may disturb the homeostatic regulatory functions of astrocytes and thus have a toxic effect on the CNS.
星形胶质细胞有助于为神经元维持适当的内环境稳定。在这些调节过程中，星形胶质细胞膜ATP酶起着重要作用。在本研究中，将星形胶质细胞培养于改良的最低必需培养基（MEM）中，并将分离的细胞膜暴露于不同浓度（3、6和9 mM）的溶剂中1小时。在暴露于芳香烃、脂环烃和脂肪烃后，测定膜结合的Na⁺、K⁺-ATP酶和Mg²⁺-ATP酶的活性。芳香烃根据其脂溶性呈剂量依赖性地降低酶活性。脂肪烃和脂环烃的轻微酶抑制作用并不取决于这些溶剂的亲脂性。它们的分子结构可能决定了溶剂的影响。在本研究中，星形胶质细胞中哇巴因敏感的Na⁺、K⁺-ATP酶活性仅占总ATP酶活性的20 - 15%，而在神经元中为45 - 55%。有机溶剂引起的酶抑制可能会干扰星形胶质细胞的内环境稳定调节功能，从而对中枢神经系统产生毒性作用。
