Pharmacological action of eptazocine (l-1,4-dimethyl-10-hydroxy-2,3,4.5,6,7-hexahydro-1,6-methano-1 H-4-benzazonine)

Pharmacological actions of eptazocine on the central nervous system were investigated by pharmacological and behavioral methods. Eptazocine produced sedation at low doses and Straub tail reaction in mice and ataxia in rats at high doses. In mice, eptazocine caused decreases in the spontaneous locomotor activities measured by the wheel cage and Animex methods, but caused an increase of the response in rats as determined by the open-field method. Eptazocine caused impairment of performance in the rotarod test and the traction test in mice, a decrease of activity of EMG, and an inhibition of flexor reflex in rats. Eptazocine decreased body temperature, potentiated pentobarbital-induced sleeping, and inhibited convulsion caused by pentylenetetrazol in mice. Fighting behavior induced by electric shock and central stimulation effect of methamphetamine were inhibited by eptazocine in mice. Eptazocine showed an inhibition of avoidance behavior in shuttle and skinner boxes in rats. These results suggest that eptazocine produces a non-specific inhibitory action on the central nervous system.