[Effects of scopolamine on morphine-dependence in mice and the relationship between the effect and hippocampus intracellular calcium].

Aim: To observe the effect and mechanism of scopolamine on morphine(Mor)-induced mice dependence.

Methods: The Mor-dependent mice model was established by intraperitoneal (ip) administered Mor for seven days. Pain threshold, times of jump and hippocampus intracellular free calcium ion concentration ([Ca2+]i) were determined by the heat plate test, naloxone (Nal)-precipitated jumping response and flow cytometry, respectively.

Results: The pain threshold of Mor-dependent mice decreased significantly while there was a marked increase in times of jump, the rate of jumping animals and hippocampus [Ca2+]i. Co-administered scopolamine, the pain threshold of Mor-dependent mice increased significantly; the number of jump, the rate of jumping animals and hippocampus [Ca2+]i all decreased significantly.

Conclusion: Scopolamine could antagonize the Mor-induced mice dependence, which could be related to decreasing the levels of brain intracellular free calcium.