| Abstract: | 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 prepared from genetically epilepsy-prone DBA/2 mice. Solutions of P. nigrum extract (0.5S, 1S and 2S) were administered when spontaneous depolarizations were well established in magnesium-free perfusing medium. The 2S extract produced a significant reduction in the number of spontaneous 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-induced depolarizations (p <0.001). The present results suggest that an antagonistic action at NMDA receptors might contribute to the anticonvulsant properties of P. nigrum. © 1997 John Wiley & Sons, Ltd. |
