EFFECTS OF ORAL AND INTRAVENTRICULAR ADMINISTRATION OF GINSENOSIDE RG1 ON THE PERFORMANCE IMPAIRED BY SCOPOLAMINE IN RATS

A single oral administration of ginsenoside Rg1 (1 and 2 mg/rat) did n ot have ameliorating effects on impaired performance caused in rats by scopolamine in a radial-arm maze. However, the oral administration of the same doses of Rg1, which was packed in an enteric capsule, improv ed the impaird performance. These results suggest that Rg1 not in the capsule was decomposed by gastric juices in the stomach and that Rg1 i n the enteric capsule was not damaged by gastric juices and reached th e intestine to be absorbed. A single intracerebroventricular injection with Rg1 at doses of 0.1 and 0.5 mu g/rat, which were ineffective whe n given intraperitoneally (9), had ameliorating effects on the impaire d performance. It seems that the brain is a target of Rg1 given system ically. The mitigating action of Rg1 is discussed in relation to the c entral cholinergic system.