Bicuculline is a phthalide-isoquinoline compound that is a light-sensitive competitive antagonist of GABAA receptors. It was originally identified in 1932 in plant alkaloid extracts and has been isolated from Dicentra cucullaria, Adlumia fungosa, and several Corydalis species (all in subfamily Fumarioideae, previously known as family Fumariaceae). Since it blocks the inhibitory action of GABA receptors, the action of bicuculline mimics epilepsy; it also causes convulsions. This property is utilized in laboratories around the world in the in vitro study of epilepsy, generally in hippocampal or cortical neurons in prepared brain slices from rodents. This compound is also routinely used to isolate glutamatergic (excitatory amino acid) receptor function.