THE ADENOSINE BINDING ENHANCER, PD-81,723, INHIBITS EPILEPTIFORM BURSTING IN THE HIPPOCAMPAL BRAIN SLICE

The effects of adenosine and the adenosine binding enhancer, PD 81,723 , on low magnesium-induced bursting in the in vitro hippocampal slice were examined. Extracellular recordings were obtained from the CA3 pyr amidal cell layer while electrically stimulating in the stratum radiat um under low magnesium perfusion. Adenosine (6-100 muM) reduced the du ration of epileptiform bursting in a dose-related manner, which was re versible upon washout of adenosine. Application of PD 81,723 (50-100 m uM) also resulted in a dose-dependent reduction in the duration of the triggered burst, which was irreversible. These results demonstrate an ticonvulsant activity of adenosine and the adenosine binding enhancer, PD 81,723, in the low magnesium model of epilepsy.