Effects of ginkgolide B on neuronal discharges in rat hippocampal CA1 area / 神经解剖学杂志

ABSTRACT

Extracellular single-unit discharge recording technique was used to examine the effects of Ginkgolide B (BN52021) on the discharges of neurons in CAI area of hippocampal slices and to elucidate the mechanisms involved.The results showed that:(1) In response to the application of ginkgolide B (0.1,1,10 βμmol/L; n =43) into the perfusate for 2 rain,the spontaneous discharge rates (SDR) of 42/43 (97.67%) neurons were significantly decreased in a dose-dependent manner; (2) Pretreatment with L-glutamate (L-Glu,0.2mmol/L) led to a marked increase in the SDR of all 10 (100%) neurons in an epileptiform pattern.The increased discharges were suppressed significantly after ginkgolide B (1 μmol/L) was applied into the perfusate for 2 rain; (3) In 8 neurons,perfusion of the selective L-type calcium channel agonist,Bay K 8644 (0.1 μmol/L),induced a significant increase in the discharge rate of 8/8 (100%) neurons.Ginkgolide B (1 μmoL/L) applied into the perfusate inhibited the discharges of 7/8 (87.5%) slices; (4) In 8 neurons,the broad potassium channels blocker,tetraethylammonium (TEA,1 mmol/L) completely blocked the inhibitory effect of ginkgolide B (1 μmol/L).These results suggest that ginkgolide B can inhibit the electrical activity of CAI neurons.The inhibitory effect may be related to the blockade of L-type voltage-activated calcium channel and may be concerned with delayed rectifier potassium channel (KDR),which indicated that ginkgolide B play a protective role on the central neurons.