Extract of Hypericum perforatum blocks nicotine-induced locomotor activity in mice

Abstract

In the present study, the effects of Hypericum perforatum on nicotine-induced locomotor activity have been investigated in mice. Adult male Swiss-Webster mice were subjects. Nicotine (0.5, 1 and 2 mg/kg) and saline were given to mice intraperitoneally. Locomotor activities of the mice were recorded for 30 min immediately following nicotine or saline administration. Hypericum perforatum extract (HPE) (6, 12, 24 and 48 mg/kg) and saline were injected to another five independent groups of the mice and 20 min later, locomotor activity was recorded for 30 min. In further study, HPE (6-24 mg/kg) was administered to other independent groups of mice 20 min before nicotine (1 mg/kg) injections and locomotor activity was recorded for 30 min immediately after nicotine administration. Nicotine (1 mg/kg) produced a significant increase in locomotor activity of the mice. HPE depressed significantly locomotor activity of the mice at dose of 48 mg/kg. Other doses of HPE (6-24 mg/kg) did not produce any significant change in the locomotor activities. HPE (24 mg/kg) blocked significantly nicotine (1 mg/kg)-induced locomotor. Our results suggest that HPE blocks nicotine-induced locomotor hyperactivity in mice. Thus, it may be a useful agent for treatment of nicotine-type dependence.