The GABA-Withdrawal Syndrome: A Model of Local Status Epilepticus

[摘要] The GABA-withdrawal syndrome (GWS)is a model of local status epilepticus followingthe interruption of a chronic GABA infusioninto the rat somatomotor cortex. GWS ischaracterized by focal epileptic electroencephalographicdischarges and associated contralateralmyoclonus. In neocorticai slices obtainedfrom GWS rats, most neurons recorded in theGABA-infused area are pyramidal neuronspresenting bursting properties. The bursts areinduced by white-matter stimulation and/orintracellular depolarizing current injectionand correlate with a decrease of cellularsensitivity to GABA, caused by its prolongedinfusion. This effect is related to a calciuminflux that may reduce theGABAAreceptormediatedinward current and is responsiblefor the bursting properties. Here we presentevidence for the involvement of calcium- andNMDA-induced currents in burst genesis. Wealso report modulatory effects of noradrenalineappearing as changes on firing patterns ofbursting and nonbursting cells. Complementaryhistochemical data reveal the existence of alocal noradrenergic hyperinnervation and anectopic expression of tyrosine hydroxylasemRNAs in the epileptic zone.

[学科分类] 精神健康和精神病学