雌激素和植物雌激素对大鼠杏仁核多巴胺能系统的调节

用快速周期伏安法(fast cyclic voltammetry,FCV)测定了动情周期各期雌鼠、去卵巢(ovaricectomized,OVX)鼠和正常雄鼠的杏仁核(amygdala,Amy)多巴胺(dopamine,DA)释放,同时应用酪氨酸羟化酶(tyrosine hydrox-ylase,TH)免疫组化技术检测了以上各组大鼠腹侧背盖区(ventral tegmental area,VTA)的TH阳性神经元数目。并在此基础上,将植物雌激素——大豆异黄酮侧脑室注射,观察了其对各组大鼠Amy DA释放的作用。结果显示,雌鼠动情前期DA释放量最高,高于其余三期和OVX鼠;AmyDA释放和VTATH阳性神经元数目存在明显的性别差异,雌性高于雄性;大豆异黄酮可快速(5min内)增加雌鼠、OVX鼠的Amy DA释放,提示大鼠内源性雌激素水平差异对中脑边缘系统DA能神经元存在调节作用,大豆异黄酮可在中枢发挥类雌激素作用,调节杏仁核DA能神经递质系统功能。

Regulation of estrogen and phytoestrogen on the dopaminergic systems of amygdala in rats

In vivo fast cyclic voltammetry (FCV) was used to investigate dopamine (DA) release fromamygdala (Amy) of female rats in different phases of estrus cycle, ovaricectomized (OVX) rats and malerats. Tyrosine hydroxylase (TH) immunohistochemistry was employed to measure the numbers of immunore-active neurons in ventral tegmental area (VTA) of midbrain in the rats. We also observed the effect of in-tracerebroventricular injection of phytoestrogen-soy isoflavones on DA release from the Amy. The results areas follows: DA release from the Amy of proestrus female rats was apparently higher than that in estrus, me-taestrus, diestrus female rats and OVX rats. Amy DA release and the numbers of the TH immunoreactiveneurons in VTA showed a significant sex difference. DA release from Amy of female and OVX rats increasedsignificantly within 5 min after i. c. v injection of soy isoflavones, which elicited no effects in male rats. Theabove -mentioned results suggest that endogenous estrogen may play an important role in regulating the ac-tivity of DA neurons in mid-limbic systems , and that soy isoflavones exert an estrogen-like effect on the do-paminergic systems in the Amy.