Background: Addiction, as a behavioral and physiological disorder, is one of the most serious challenges facing all communities. The aim of this study was to examine the effect of memory attenuation by cholinergic antagonist and light music on morphine dependency.

Materials and Methods: In this study, 70 male mature mice (weight, 30-35g) were divided into the control, witness and experimental groups. The experimental groups were treated with morphine, trihexyphenidyl, light music, morphine+trihexyphenidyl, morphine+light music, respectively. Morphine was used to create dependency and trihexyphenidyl as a memory attenuation agent. Instrumental music was also used to examine the relaxing effects of music. To estimate the level of dependency, conditioned place preference (CPP) was used.

Results: There was no significant difference in CPP between the control and witness, trihexyphenidyl, and light music groups. A significant increase was seen between the morphine and control group (P≤0.05), while a significant decrease was seen between the morphine+trihexyphenidyl and morphine group (P≤0.05). In addition, a significant increase was seen between morphine+light music and morphine group (P≤0.05). These results were continued for eight days after eliminating the drug and music.

Conclusion: Trihexyphenidyl and light music may decrease and increase morphine-induced- CPP, respectively through the inhibition and stimulation of dopaminergic neurons.