吗啡依赖对大鼠伏隔核神经甾体和氨基酸递质的影响

目的　利用大鼠吗啡依赖模型,观察吗啡依赖及戒断对大鼠伏隔核中神经甾体和氨基酸类神经递质水平影响。方法　腹腔注射递增剂量的盐酸吗啡使雄性SD大鼠形成吗啡依赖,并用纳洛酮催促戒断。分离吗啡依赖和戒断大鼠的伏隔核。经液液萃取和固相萃取法提取脱氢表雄酮、孕烯醇酮、别孕烯醇酮、脱氢表雄酮硫酸酯和孕烯醇酮硫酸酯,并采用高效液相色谱质谱系统检测其含量。采用柱前衍生-电化学检测-高效液相色谱法测定甘氨酸、谷氨酸和γ氨基丁酸的含量。结果　与对照组相比,纳洛酮催促戒断时,吗啡依赖大鼠伏隔核脱氢表雄酮硫酸酯的水平下降(P<0 .05),孕烯醇酮(P<0 .01 )和谷氨酸(P<0 .05 )水平均升高。结论　吗啡戒断时大鼠伏隔核的谷氨酸系统处于兴奋状态,伏隔核中的内源性神经甾体在吗啡依赖和戒断的形成中发挥作用。

Effect of morphine dependence on the levels of neurosteroids and amino acid transmitters in rat nucleus accumbens

Aim To detect the effect of morphine dependence and withdrawal on the levels of neurosteroids and amino acid neurotransmitters in nucleus accumbens in rat morphine dependent model. Methods Nucleus accumbens was dissected out from morphine dependent and naloxone precipitated withdrawal rats. The contents of neurosteroids including dehydroepiandrosterone, pregnenolone, allopregnanolone, dehydroepiandrosterone sulfate and pregnenolone sulfate were detected with liquid chromatography-negative atmospheric pressure with ionization mass spectrometry(LC-MS). The contents of glycine, glutamate and γ-aminobutyric acid were quantitated by HPLC-ECD with precolumn derivatization. Results Compared with saline group,in nucleus accumbens of morphine withdrawal rats, the level of dehydroepiandrosterone sulfate (P<0.05) decreased significantly but the levels of pregnenolone (P<0.01) and glutamate (P<0.05) increased significantly. Conclusion The glutamatergic system in nucleus accumbens is in excitatory state in morphine withdrawal rats. The endogenous neurosteroids system of nucleus accumbens plays a role in morphine dependence and naloxone precipitated withdrawal.