Effects of DX-9386, a traditional Chinese medicinal prescription, on long-term potentiation in the dentate gyrus in rats.

DX-9386, a traditional Chinese medicinal prescription consisting of ginseng, polygala, acorus and hoelen in the ratio of 1:1:25:50 (dry weight), was studied regarding the formation of long-term potentiation (LTP) in the dentate gyrus of anesthetized rats. Single oral administration of DX-9386 did not affect LTP formation evoked by suprathreshold tetanic stimulation; however, it significantly intensified the spike amplitude evoked by a subthreshold stimulation. LTP formation induced by suprathreshold tetanus was significantly inhibited by ethanol given either orally or intracerebroventricularly. DX-9386 significantly antagonized this inhibitory effect of ethanol. Basal spike amplitude was not influenced by DX-9386. These results indicate that DX-9386 potentiated LTP formation in the hippocampus and suggest that the ameliorative effect of this prescription on learning deficit model animals was, at least partly, due to its direct action on the hippocampus.