Arachidonic acid and its metabolites are involved in the expression of neocortical spike-and-wave spindling episodes in DBA/2J mice

This work was undertaken to study the effects of dexamethasone, indometacin and mifepristone plus dexamethasone on the neocortical spike-a nd-wave spi ndling episodes (S&W) in the electrocorticogram of DBA/2J mice. Our data in dicate that both dexamethasone and indometacin (1, 10, 100 mug kg(-1), i.p. ) reduced the S&W of DBA/2J mice, This effect appeared 30 min after drug ad ministration and lasted for the duration of the recording period (240 min). Mifepristone, a glucocorticoid receptor antagonist (1, 10, 100 mug kg(-1), i.p.), injected 2 h before dexamethasone, totally blocked the steroid effe ct. These results indicate that both dexamethasone and indometacin signific antly reduce the S&W of DBA/2J mice, suggesting a possible involvement of a rachidonic acid and its metabolites in the development of brain excitabilit y.