Effect of cyclic AMP on mesaconitine-induced analgesia in mice.

The effects of cyclic AMP, dibutyryl cyclic AMP, theophylline, isoproterenol and propranolol on mesaconitine (MA)-induced antinociception in mice were investigated employing the tail flick and acetic acid-induced writhing methods for the evaluation of antinociceptive activity. MA-induced antinociception was significantly potentiated by cyclic AMP and dibutyryl cyclic AMP. The phosphodiesterase inhibitor theophylline also significantly potentiated the MA-induced antinociception. Further, MA-induced antinociception was markedly increased by a beta-adrenoceptor agonist, isoproterenol, and reduced by a beta-adrenoceptor antagonist, propranolol. These results suggest that the antinociceptive action of MA is potentiated through cyclic AMP and stimulation of the central beta-adrenergic system.