Effect of Intracerebroventricular Morphine Withdrawal on Anxiety Behavior in Male Rats Reared in Social Isolation

 Narcotics prescription has controversial effects on the occurrence of anxiety processes; however, its acute and chronic effects on behavioral differences in social isolation are unclear in the processes of dependence and withdrawal. The present study aimed to investigate the effects of acute and chronic intracerebroventricular morphine sulfate withdrawal on the fear and anxiety behaviors of male rats reared in social isolation. 

 The present experimental study investigated 32 male 21-day-old male weaned Wistar rats that were divided into two groups of saline (control) and morphine receivers (test). They were then divided into acute and chronic subgroups that were reared under social isolation conditions. The rats of the acute daily consumption group received 10 μg/kg of morphine sulfate solution via intracerebroventricular injection for 10 days, but the chronic rats received it for 60 days. After the end of dependence by its withdrawal, the rats were quitted for 5 days, and their anxiety levels were measured using the Elevated Plus Maze (EPM). The obtained data were analyzed in SPSS using one-way Analysis of Variance (ANOVA), Tukey’s posthoc test and Paired Samples t-test.

 The research results indicated that the percentage of time and number of open arm entries in rats reared in social isolation significantly decreased during the dependence phase and 5 days after withdrawal in acute and chronic groups (P<0.001). Furthermore, their anxiety rate increased compared to the control group. The findings also suggested a higher incidence of anxiety among chronic consumer groups than acute consumer groups after abstinence.

 The study findings indicated that the discontinuation of morphine consumption in social isolation could increase the incidence of anxiety behaviors in rats. Therefore, negative emotional states associated with acute and chronic morphine withdrawal could lead to anxiety-like behaviors.Keywords: Anxiety, Morphine, Social isolation, Rats.