antinociceptive effect of the aqueous extract obtained from foeniculum vulgare in mice: the role of histamine h1 and h2 receptors

foeniculum vulgare (fennel) has been widely used in traditional medicine for treatment of variousdiseases including pediatric colic. this study was designed to assess the antinociceptive effects of aqueousextract of f. vulgare on visceral pain and possible involvement of opioidergic, serotonergic, adrenergic andhistaminergic systems. the results of this study showed that aqueous extract of f. vulgare (50, 100 and 200mg/kg, ip) induces antinociceptive effects (pcimetidine significantly attenuate this effect (from 71.9% to 21.6%, pp=0.003, respectively). furthermore, chlorpheniramine and cimetidine significantly decreased onset of first abdominal writhing (latency) in comparison with extract (pphentolamine had no effect on antinociception and the latency induced by f. vulgare. the ed50 value for antinociceptive effects of extract was 87.6 mg/kg. these results suggest that antinociceptive effects of f. vulgare are partially mediated by histamine h1 and h2 receptors.