Glial membrane channels and receptors in epilepsy: impact for generation and spread of seizure activity.

Epilepsy is a condition in the brain characterized by repetitively occurring seizures. While various changes in neuronal properties have been reported to accompany or induce seizure activity in human or experimental epilepsy, other studies suggested that glial cells might be involved in epileptogenesis. Recent findings demonstrate that in the course of the disease, glial cells not only undergo structural alterations but also display distinct functional properties. Several studies identified reduced inwardly rectifying K(+) currents in astrocytes of epileptic tissue, which probably results in disturbances of the K(+) homeostasis. Other data hinted at an abnormal increase in [Ca(2+)](i) in astrocytes through enhanced activity of glial glutamate receptors. This review summarizes current knowledge of alterations of plasma membrane channels and receptors of macroglial cells in epilepsy and discusses the putative importance of these changes for the generation and spread of seizure activity.