Effect of Memory Attenuation on Creating Morphine Dependency in Male Mature Mice

Background : Morphine and other addicting drugs induce an uncontrolled desire in man to consume the drugs overtly and stimulate the brain compensative systems such that the neuron sensitivity produced is not desensitized for some time after the consumption and detoxification of the drug. Therefore, the aim of this study is to examine the effect of memory attenuation in creating morphine dependency.
Materials and Methods : In this study, 60 male mature mice (85 days old) with a weight of 30-35 grams were enrolled as the experimental and the control groups. The experimental groups included 3 subgroups treated with morphine, scopolamine or morphine+ scopolamine, respectively. Morphine was used for dependency and scopolamine for memory attenuation. Conditioned place preference (CCP) method was used to estimate dependency.
Results : Results showed no meaningful difference between the control and the witness groups and between the control and scopolamine groups in preferring a special location to receive the drug. However, there was a meaningful difference (p<0.05) between the control and the morphine groups in preferring a location to receive morphine, and a meaningful attenuation was observed in the scopolamine+morphine group in preferring the location for receiving the drug compared with the group receiving morphine alone.
Conclusion : The results show that through memory attenuation, scopolamine decreases morphine dependent CPP. Binding of scopolamine to muscarinic receptors and blocking them affects the opioid receptors which together with reduced nitric oxide synthesis and decreased intracellular calcium, reduces the morphine-induced CPP.