Abstract

The nicotinic cholinergic receptors have been reported to be involved in several actions of cannabinoids (e.g., bradycardia, hypothermia). However, the influence of central cholinergic system on cannabinoids antinociceptive effect has not been reported. This study investigated the possible part played by nicotinic cholinergic modulator drugs on the antinociceptive effect of central administration of arachidonylcyclopropylamide (ACPA) in mice. The antinociceptive effects of intracerebroventricular (i.c.v.) administration of ACPA using the formalin test have been studied in mice. The effects of nicotine or mecamylamine (a nicotinic cholinergic antagonist) on ACPA analgesia are also studied. i.c.v. administration of ACPA (0.004-1 mu g/mice) induced antinociceptive effect in mice. i.c.v. administration of nicotine (0.1 or 0.5 mu g/mice) or mecamylamine (2 mu g/mice) potentiated or antagonized ACPA antinociceptive effects, respectively. It is concluded that ACPA-induced analgesia is influenced by central nicotinic cholinergic activity.