雌激素受体α和TrkA在基底前脑的分布与共存

基底前脑为神经营养因子和雌激素作用的靶区之一。为了在受体水平探讨这些配体是否作用于正在发育和成年大鼠的基底前脑同一神经元 ,本文采用免疫组织化学双重反应方法观察了雌性大鼠雌激素受体α和酪氨酸激酶 A在基底前脑的分布与共存。用小鼠抗雌激素受体和兔抗酪氨酸激酶 A分别孵育切片 ,ABC法显示前者的反应产物主要位于胞核内 ,蓝黑色 ,呈点状 ;后者位于胞质和突起内 ,呈棕色。结果表明 :两者都分布于基底前脑神经元。在双重免疫组织化学反应条件下可见三种细胞 :雌激素受体阳性细胞 ,酪氨酸激酶 A阳性细胞和双重反应阳性细胞 ,双重反应阳性细胞所占的比例因部位而不同。雌激素受体和酪氨酸激酶 A共存提示它们的配体可通过共存于基底前脑同一神经细胞上的相应受体而作用于同一神经元 ,协同地调节特异的基因或者基因网络的表达 ,从而影响神经元的存活、分化、成熟、再生和可塑性

THE DISTRIBUTION AND COEXISTENCE OF ESTROGEN RECEPTOR alpha AND TrkA IN NEURONS OF THE BASAL FOREBRAIN IN THE RAT

The basal forebrain is one of the targets of neurotrophins and estrogen, both of which have been implicated in cholinergic function. To investigate whether or not these ligands may act on the same neurons in the developing and adult rat basal forebrain, double labeling immunohistochemical ABC technique was used to study the distribution and coexistence of estrogen receptor and TrkA in the basal forebrain of the female rats. Separated incubation of the brain sections were made with mouse anti ER and rabbit anti TrkA. ER staining consisted of punctate blue/black reaction products which are mostly localized to the nucleus whereas TrkA staining consisted of brownish reaction products within the cytoplasm and processes of the neurons. The results indicated that ER and TrkA were distributed in neurons of the basal forebrain. There were three kinds of immunoreactive cells: (1) ER single labeled cells; (2) TrkA single labeled cells; and (3) ER/TrkA double labeled cells. The ratio of double labeled cells to all kinds of labeled cells was varied according to location and age. Colocalization of ER and TrkA implies that their ligands may act on the same neuron by corresponding receptor, perhaps synergistically, to regulate the expression of specific genes or gene networks that may influence neuronal survival, differentiation, maturation, regeneration, and plasticity. (Figures 1～4 on plate 24)