Pandaranandaka Jantarima, Poonyachoti Sutthasinee, Kalandakanond-Thongsong Sarinee
Interdepartment of Physiology, Graduate School, Chulalongkorn University, Henri Dunant Road, Bangkok 10330, Thailand.
Physiol Behav. 2006 Apr 15;87(4):828-35. doi: 10.1016/j.physbeh.2006.02.002. Epub 2006 Mar 6.
Anxiety is a symptom reflecting the dysregulation of monoaminergic neurotransmitters which may be modulated by estrogen. In our current study, we investigated the effects of chronic estrogen administration (10 microg/kg, s.c. for 4 weeks) on anxiety-like behavior using the elevated plus-maze with the corresponding changes of monoamines in the brain regions contributing to anxiety. The behavioral test revealed that estrogen-treated rats (Ovx+E(2)) spent more time in the open arm of the maze as well as a higher time/entry ratio in open arms than ovariectomized (Ovx) rats, indicating an anxiolytic property of estrogen. The increase in open arm time corresponded to an increase in uterine weight, indicated a correlation between the function of estrogen and its anxiolytic effect. Measurements of brain monoamines following estrogen treatment revealed decreases in norepinephrine, dopamine and serotonin in all of the brain regions studied, which also lead to an increase in turnover rates. The concentrations of norepinephrine in caudate putamen, of dopamine in nucleus accumbens, of serotonin in frontal cortex, hippocampus, caudate putamen, nucleus accumbens, and substantia nigra and of the serotonin metabolite, the 5-hydroxyindolacetic acid in substantia nigra of Ovx+E(2) rats were significantly lower than those of Ovx rats. Interestingly, the uterine weight was negatively correlated with the changes of dopamine and serotonin (with the exception of the hippocampus), suggesting a regulatory role of estrogen on these systems. From these data, we concluded that, in fact, there is a relationship between estrogen and monoamines (i.e. serotonin, dopamine) in modulating the anxiety-like behaviors in female rats.
焦虑是一种反映单胺能神经递质失调的症状，而雌激素可能对其有调节作用。在我们目前的研究中，我们使用高架十字迷宫研究了慢性给予雌激素（10微克/千克，皮下注射4周）对焦虑样行为的影响，以及对参与焦虑调节的脑区中单胺类物质相应变化的影响。行为测试显示，接受雌激素处理的大鼠（去卵巢+雌二醇组，Ovx+E(2)）在迷宫开放臂中停留的时间比去卵巢大鼠（Ovx）更长，且在开放臂中的时间/进入次数比值更高，这表明雌激素具有抗焦虑特性。开放臂停留时间的增加与子宫重量的增加相对应，这表明雌激素功能与其抗焦虑作用之间存在相关性。雌激素处理后对脑单胺类物质的测量显示，在所研究的所有脑区中，去甲肾上腺素、多巴胺和5-羟色胺均减少，这也导致了周转率的增加。Ovx+E(2)大鼠尾壳核中的去甲肾上腺素浓度、伏隔核中的多巴胺浓度、额叶皮质、海马、尾壳核、伏隔核和黑质中的5-羟色胺浓度以及黑质中5-羟色胺代谢产物5-羟吲哚乙酸的浓度均显著低于Ovx大鼠。有趣的是，子宫重量与多巴胺和5-羟色胺的变化呈负相关（海马除外），这表明雌激素对这些系统具有调节作用。从这些数据中，我们得出结论，事实上，雌激素与单胺类物质（即5-羟色胺、多巴胺）在调节雌性大鼠焦虑样行为方面存在关联。
