Panax ginseng on Brain and Hypothalamic 5-hydroxytryptamine during Immobilization Stress: and its Modification by Parachlorophenylalanine

The involvement of central 5-hydroxytryptamine (5-HT) in the anti-stress effects of Panax ginseng was studied in immobilized rats after blockade of 5-HT synthesis with parachlorophenylanine (PCPA). Materials and methods : Adult male Wistar rats were pretreated with PCPA (100 mg/kg, i.p.) once daily for 3 days. Panax ginseng (50 mg/kg, i.p.) was administered 30 min before the rats were subjected to immobilization stress (IS) for 1 h. The levels of 5-HT in brain and hypothalamus, and plasma corticosterone, were measured spectrofluorometrically. Results : IS for 1 h resulted in enhanced 5-HT levels in brain and hypothalamus and increase in plasma corticosterone. Administration of PCPA reduced all the above parameters. Panax ginseng significantly attenuated IS-induced elevations in the above parameters when either given alone or when co-administered with PCPA. Conclusions : These data suggest that anti-stress effect of Panax ginseng may be modulated by central 5-HT-ergic system.