ABSTRACT
There is some evidence about the role of estrogen in the nervous system such, as increasing plasticity in different areas of brain and interference phenomena like reproduction, pain and memory. Results of some investigation indicate the neuromodulatory effect of estrogen. In this study, the effect of estradiol benzoate in morphine dependency was investigated. Material and Albino mice weighing 25 +/- 3 grams, were divided to in to control [sham operation], ovariectomized, ovariectomized receiving sesame oil and acute and chronically administrered estradiol benzoate groups. Addiction was induced in all animals by morphine injections 3 times per day, for four days. On the fourth day, half an hour before induction of withdrawal syndrome naloxone, stradiol benzoate were acutely injected [0.1 mg/kg, SC] and jumping of animals as a sign of withdrawal syndrome was assessed. Chronic treatment of estradiol benzoate was co-administered with morphine on four the day. The results showed that ovarectomy decreased jumping activity of withdrawal syndrome or intensity of morphine-dependency and estradiol benzoate treatment partially increased this sign of the withdrawal syndrome although but it was less than the control groups. The results suggest that the other sex related factors probably influence the intensity of morphine dependency