Objective: To observe the inhibitory effect of melatonin on morphine withdrawal syndromes and serum monoamines in morphine dependent mice.
Methods: A physical dependent model in mice was established by subcutaneous injection of morphine. The intensity of withdrawal syndromes was evaluated according to the jumping latency and jumping times. The concentration of serum monoamines was detected with HPLC-ECD.
Results: The physical withdrawal syndromes in morphine dependent mice were inhibited partly by four different doses (25, 50, 100, 200 mg/kg) of melatonin and showed a significant dose-dependent manner. The increased concentration of serum norepinephrine and dopamine in morphine-dependent mice could be reduced by large dose (100 mg/kg) of melatonin.
Conclusion: The jumping withdrawal syndromes and serum monoamiues in morphine-dependent mice could be inhibited partly by melatonin.