Gut and brain effects of American ginseng root on brainstem neuronal activities in rats.

Brainstem neurons receiving subdiaphragmatic vagal inputs were recorded in an in vitro neonatal rat brainstem-gastric preparation. Aqueous extracts of American ginseng root (Panax quinquefolium L.) were applied to the gastric compartment or the brainstem compartment of the bath chamber to evaluate the peripheral gut and central brain effects of the extracts on brainstem unitary activity. After Panax quinquefolium L. application to the gastric or brainstem compartment, a concentration-related inhibition in neuronal discharge frequency in the brainstem unitary activity was observed, suggesting that Panax quinquefolium L. may play an important role in regulating the digestive process and modulating brain function. In this study, pharmacological effects of American-cultivated Panax quinquefolium L. and Chinese-cultivated Panax quinquefolium L. were also compared. Our results suggest that American-cultivated Panax quinquefolium L. possesses a significantly stronger gastric modulating effect on brain neuronal activity.