ELECTROPHYSIOLOGICAL APPROACH OF THE ANTIEPILEPTIC EFFECT OF DEXAMETHASONE ON HIPPOCAMPAL SLICE CULTURE USING A MULTIRECORDING SYSTEM - THEPHYSIOCARD(R)

The in vitro antiepileptic activity of the synthetic glucocorticoid de xamethasone (DEX) was tested in rat hippocampal organotypic cultures o n the field potential epileptiform activity induced by picrotoxin (PTX ). Spontaneous as well as evoked electrophysiological activities have been studied through the extracellular multirecording Physiocard(R) sy stem. PTX typically elicited seizure-like discharges (epileptiform bur sts) in the hippocampus neurons. Those epileptiform bursts can be divi ded in two groups, one rhythmic which lasted 43+/-24s (mean+/-sd) at a frequency of 4.6+/-1.9Hz and the other arhythmic composed of populati on spikes, which occurred during 14.3+/-6.9min. In the presence of DEX at different concentrations, results obtained were 1) DEX 1 mu M decr eased the occurrence of the two different groups of spontaneous epilep tiform bursts, most of the time to zero. 2) DEX 50 mu M prevented tota lly the occurrence of epileptiform bursts. 3) DEX 50 mu M contrarily t o DEX 1 mu M avoided the decrease of evoked field potentials' amplitud e induced by PTX 3 mu M on all simultaneous recorded points. Those res ults suggest that synthetic glucocorticoid DEX presents an acute antie pileptic effect in a dose dependent manner on the hippocampus tissue. (C) 1997 Elsevier Science Inc.