Читать книгу Canine and Feline Epilepsy - Luisa De Risio - Страница 48

Glial uptake of perisynaptic glutamate is the major mechanism forestalling accumulation of glutamate at the synapse (Benarroch, 2005). Astrocytes have an equally important role in the regulation of extracellular potassium. Astrocytic buffering of potassium maintains extracellular levels below a ceiling of 12 mM (Benarroch, 2005). In some cases, such as the epileptic brain, glia may also release glutamate, thereby prolonging post-synaptic excitation. Tian et al. (2005) recently showed that glial release of glutamate contributed to the maintenance of the paroxysmal depolarizing shift that is the hallmark of ‘epileptic’ neurons. Failure of glia to buffer extracellular glutamate, let alone glutamate release from glia, can be expected to result in prolonged excitatory drive and seizure maintenance.