Astrocytes in methylmercury, ammonia, methionine sulfoximine and alcohol-induced neurotoxicity

Astrocytes occupy similar to 25% of the CNS volume. Their "foot" processes are closely associated with synapses, nodes of Ranvier, axonal tracts, and capillaries. Astrocytic functions include neurotrophic factor secretion, co ntrol of extracellular pH, inactivation of glutamate, as well as uptake and metabolism of neurotransmitters. Astrocyte-neuron interactions provide str ategic sites for actions of numerous chemical compounds. In this manuscript , we discuss examples of toxins that directly affect astrocyte function (me thylmercury, ammonia, methionine sulfoximine, and alcohol), leading to an a ltered homeostatic control of the extracellular milieu and neuronal dysfunc tion. In addition, the potential role of astrocytic proteins, the metalloth ioneins, in attenuating the neurotoxicity of methylmercury is discussed. (C ) 2000 Inter Press, Inc.