EFFECTS OF PIPER-NIGRUM L ON EPILEPTIFORM ACTIVITY IN CORTICAL WEDGESPREPARED FROM DBA 2 MICE/

This study investigated the effect of a water extract of Piper nigrum L. on spontaneous depolarizations, accompanying afterpotentials and N- methyl-D-aspartate (NMDA)-induced depolarizations in cortical wedges p repared from genetically epilepsy-prone DBA/2 mice. Solutions of P. ni grum extract (0.5S, 1S and 2S) were administered when spontaneous depo larizations were well established in magnesium-free perfusing medium, The 2S extract produced a significant reduction in the number of spont aneous depolarizations (p<0.001) whilst the number of afterpotentials per burst was suppressed significantly by 1S and 2S (p<0.05 and p<0.01 , respectively). P. nigrum also decreased the amplitude of NMDA-induce d depolarizations (p<0.001). The present results suggest that an antag onistic action at NMDA receptors might contribute to the anticonvulsan t properties of P. nigrum. (C) 1997 by John Wiley & Sons, Ltd.