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Extract of Hypericum perforatum blocks caffeine‐induced locomotor activity in mice: a possible role of nitric oxide
Author(s) -
Uzbay I. Tayfun,
Coskun Ilke,
Kayir Hakan,
Ozturk Nilgun,
Ozturk Yusuf
Publication year - 2007
Publication title -
phytotherapy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 129
eISSN - 1099-1573
pISSN - 0951-418X
DOI - 10.1002/ptr.2085
Subject(s) - caffeine , locomotor activity , pharmacology , nitric oxide , saline , chemistry , inhibitory postsynaptic potential , arginine , motor activity , endocrinology , medicine , biochemistry , amino acid
The present study investigated the effects of HPE on caffeine‐induced locomotor activity in mice. Caffeine (4–16 mg/kg) or saline were given to adult male Swiss‐Webster mice, and the locomotor activity was immediately measured for 30 min. HPE (6–48 mg/kg) and saline were injected to another group of mice and the locomotor activity was measured 20 min later. HPE (6–24 mg/kg) was also administered to another group of mice 20 min before caffeine (16 mg/kg) injections and the locomotor activity was recorded for 30 min immediately after caffeine administrations. Finally l ‐arginine (1 g/kg) was administered i.p. 20 min before HPE (6 mg/kg) and the locomotor activity was measured as mentioned above. Each group of mice was used only once. Caffeine produced some significant increases in locomotor activity of the mice. HPE (6–24 mg/kg) significantly blocked the caffeine‐induced locomotor hyperactivity. Pretreatment of l ‐arginine (1 g/kg) reversed the inhibitory effect of HPE (6 mg/kg) on caffeine‐induced locomotor activity without producing any significant effect on locomotor activity of the mice when it was administered alone. The results suggest that HPE blocks caffeine‐induced locomotor hyperactivity in mice. Furthermore, the inhibitory effect of HPE on caffeine‐induced locomotor activity may be related to its NOS inhibitory property. Copyright © 2007 John Wiley & Sons, Ltd.