Johansson P, Ray A, Zhou Q, Huang W, Karlsson K, Nyberg F
Department of Pharmaceutical Biosciences, Division of Biological Research on Drug Dependence, Uppsala, Sweden.
Neurosci Res. 1997 Feb;27(2):185-9. doi: 10.1016/s0168-0102(96)01141-8.
The levels of beta-endorphin and Met-enkephalin-Arg-Phe (MEAP) immunoreactivity in various brain regions (including amygdala, cortex, hippocampus, hypothalmus, nucleus accumbens, pituitary and ventral tegmental area) were studied in male rats subjected to daily intramuscular injections during 14 days of high doses (5 and 15 mg/kg) of the anabolic androgenic steroid (AAS), nandrolone decanoate. At the nandrolone dose of 15 mg/kg a significant (about 20-fold) increase in beta-endorphin levels in the ventral tegmental area (VTA) was observed. The steroid did not significantly affect the concentration of the peptide at any dose in other brain areas examined. The levels of MEAP remained unaltered in all studied regions. A slight increase in serum concentrations of both peptides was also found but this elevation was not statistically significant. The observed increase in beta-endorphin in VTA was suggested to be involved in a mechanism by which the steroid may influence the reward system in the brain. An opioid mediated stimulation of the reward system following injection of AAS supports a previous hypothesis that AAS may induce psychological dependence.
在连续14天每天给雄性大鼠肌肉注射大剂量（5和15毫克/千克）合成代谢雄激素类固醇（AAS）癸酸诺龙的实验中，研究了其在各个脑区（包括杏仁核、皮层、海马体、下丘脑、伏隔核、垂体和腹侧被盖区）中的β-内啡肽和甲硫氨酸脑啡肽-精氨酸-苯丙氨酸（MEAP）免疫反应水平。在癸酸诺龙剂量为15毫克/千克时，观察到腹侧被盖区（VTA）中的β-内啡肽水平显著升高（约20倍）。在其他所检查的脑区中，该类固醇在任何剂量下均未显著影响该肽的浓度。在所有研究区域中，MEAP水平均未改变。还发现两种肽的血清浓度略有升高，但这种升高无统计学意义。观察到的VTA中β-内啡肽的增加被认为参与了该类固醇可能影响大脑奖赏系统的机制。注射AAS后阿片类物质介导的奖赏系统刺激支持了先前的一个假设，即AAS可能诱导心理依赖。
