Involvement of central cholinergic system in antinociception induced by sumatriptan in mouse

The antinociceptive effect of the antimigraine drug sumatriptan was assessed in mice (hot-plate and abdominal constriction tests). Antinociception induced by sumatriptan (10-30 mg kg-1 i.p.) was prevented by the muscarinic antagonist atropine (5 mg kg-1 i.p.), the ACh-depletor hemicolinium-3 (1 microgram per mouse i.c.v.) and the 5-HT1A antagonist NAN-190 (0.5 mg kg-1 i.p.). Naloxone, CGP-35348 and reserpine administered in doses suitable for blocking analgesia respectively induced by morphine, baclofen and clomipramine did not modify sumatriptan antinociception. On the basis of the above findings, we can deduce that sumatriptan was able to induce antinociception by increasing cholinergic neurotransmission through the stimulation of 5-HT1A receptors.