Effect of glucocorticoid on ¦Ìª²opioid receptor in morphine dependent rats

    REN Bo1, WANG Xinª²Hua2, WU Hong3, SHI Xueª²Yin2

    1Department of Anesthesiology, Chinese PLA 302 Hospital, Beijing 100039, China, 2Department of Anesthesiology, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China, 3Department of Chemistry, School of Pharmacology, Fourth Military Medical University, Xi¬ðan 710033, China

    ¡¾Abstract¡¿ AIM: To explore the molecular mechanism of glucocorticoid in the treatment of opioid withdrawal syndromes and the localization of ¦Ìª²opioid receptor. METHODS: Rats received administration of morphine by intraperitioneal injection with dose adding progressively to develop the addiction model. Twentyª²four rats were randomly assigned into three groups and received different kinds of treatment. Naloxone was administrated to precipitate withdrawal syndromes. Immunohistochemical staining was used to detect the localization of ¦Ìª²opioid receptor. RESULTS: The withdrawal syndromes in glucocorticoid group were alleviated more distinctly than those in morphine group. The expression of ¦Ìª²opioid receptor protein was lower in hippocampus, hypothalamus, locus coreuleus, ventral tegmental area (VTA) and nucleus accumbens (NAc) of morphine dependent rats. CONCLUSION: Glucocorticoid produces some suppressing effect on the withdrawal syndromes of morphine dependent rats. The ¦Ìª²opioid receptor may regulate the activities of rewarding systems by presynaptic mechanism. ......