Shimotsu-to improves transient cerebral ischemia and scopolamine-induced impairment in passive avoidance performance in mice

摘要

In the previous paper, our group reported that Shimotsu-to improved scopolamine-induced spatial cognitive deficits in rats using an 8-arm radial maze. In the present study, we investigated the effect of Shimotsu-to on the impairment induced by transient cerebral ischemia in mice in passive avoidance performance. Shimotsu-to (6.0 g/kg, p.o.) administered one hour before operation showed the protective effect on impairment induced by the cerebral ischemia reperfusion. We also studied the efficacy of Shimotsu-to and its four crude fractions, Angelica Root, Cnidium Rhizome, Peony Root and Rehmannia Root on scopolamine-induced acquisition impairment. Shimotsu-to prevented scopolamine-induced acquisition impairment at dose of 1.5 and 6.0 g/kg (p.o.). Among the four constituents, Angelica and Peony prolonged the latency of step-down and decreased the number of errors in the retention trial at a high dose (1.5 g/kg, p.o.). Whereas Rehmannia and Cnidium did not show any effect in the same performance. These results suggested that Angelica and Peony played an important role in the anti-amnesic effect of Shimotsu-to. The effect of Shimotsu-to on amnesia could not be explained entirely by the contribution of Angelica and Peony. The absence of any one of its constituents resulted in the loss of activity.