Changes of dopamine neurotransmitter and its receptor in striatum from conditioned place preference of rats administrated of morphine / 中华行为医学与脑科学杂志

ABSTRACT

Objective To observe the level of dopamine and its receptor in striatum from conditioned place preference (CPP) of rats administrated of morphine.And explore the mechanism of opioid-psychic dependence involving the levels of neurotransmitter and receptor.Methods CPP model was validated in morphine-dependence rats for 10 days.Striatum samples were harvested from two separate groups involving the saline group and morphine treated group (n =10 per experiment).The DA contents in striatum were detected in rats with colorimetry.Immunohistochemistry was applied to detect the differential expression levels of dopamine receptor 2 (DRD2)in samples.Results Compared with the saline group,higher content of neurotransmitter dopamine was observed in the morphine dependent rats (7.63 ±0.98 vs 5.23 ± 1.01,P＜0.01),while the expression level of DRD2 was down regulated (0.06 ± 0.02 vs 0.08 ± 0.02,P ＜ 0.01).Conclusion The increased expression of neurotransmitter dopamine and the decreased of DRD2 may be contributed to morphine-induced psychological dependence in morphine dependent rats.