Alpha-oestrogen and progestin receptor expression in the hypothalamus and preoptic area dopaminergic neurones during oestrous in cycling rats
Alpha-oestrogen and progestin receptor expression in the hypothalamus and preoptic area dopaminergic neurones during oestrous in cycling rats
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DOI：
10.1111/j.1365-2826.2007.01624.x
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发表时间：
2008-01-01
影响因子：
3.2
通讯作者：
Anselmo-Franci, J. A.
中科院分区：
文献类型：
--
作者：
Leite, C. M.;Szawka, R. E.;Anselmo-Franci, J. A.
催乳素分泌高峰出现在发情大鼠发情当天下午。虽然催乳素受卵巢类固醇的调节，但发情期间血浆雌二醇和孕酮水平没有变化。由于催乳素的释放受到下丘脑多巴胺的强直抑制和视前区(POA)多巴胺传递的调节，本研究旨在探讨雌激素受体(ER)-α和孕激素受体(PR)在发情期间弓状核(ARC)、脑室周围核(AVPe)、前腹侧脑室周围核(AVPe)和视前内侧核(VMPO)多巴胺能神经元中的表达变化。从发情期10~20h开始，每隔2 h灌流一次。脑切片被双重标记为ERα或PR和酪氨酸羟化酶(TH)。TH免疫反应(Ir)神经元的数量在任何被评估的区域中都没有显著差异。ERα在TH阳性神经元中的表达在吻侧ARC和背内侧ARC的14h和16h，在尾侧ARC的14h和VMPO的16h增加，而在腹外侧ARC、脑室周围和AvPe的表达没有变化。在下午，脑室周围和吻侧、背内侧、腹外侧区和尾侧区的TH阳性神经元中PR的表达呈一过性下降，在14~16h达到最低水平，但在AVPe和VMPO中的表达没有变化。发情期间血浆雌二醇和孕酮浓度较低且没有变化，表明受体表达的变化可能不是由于配体水平的变化。因此，我们的数据表明，ERα和PR表达的变化可能促进下丘脑内侧基底核和POA多巴胺能神经元活性的变化，即使在卵巢类固醇分泌不变的情况下也是如此，这可能促进发情时催乳素激增的发生并调节其幅度。
A secretory surge of prolactin occurs on the afternoon of oestrous in cycling rats. Although prolactin is regulated by ovarian steroids, plasma oestradiol and progesterone levels do not vary during oestrous. Because prolactin release is tonically inhibited by hypothalamic dopamine and modulated by dopamine transmission in the preoptic area (POA), the present study aimed to evaluate whether oestrogen receptor (ER)-alpha and progestin receptor (PR) expression in the dopaminergic neurones of arcuate (ARC), periventricular, anteroventral periventricular (AVPe) and ventromedial preoptic (VMPO) nuclei changes during the day of oestrous. Cycling rats were perfused every 2 h from 10-20 h on oestrous. Brain sections were double-labelled to ER alpha or PR and tyrosine hydroxylase (TH). The number of TH-immunoreactive (ir) neurones did not vary significantly in any area evaluated. ER alpha expression in TH-ir neurones increased at 14 and 16 h in the rostral-ARC and dorsomedial-ARC, 14 h in the caudal-ARC and 16 h in the VMPO, whereas it was unaltered in the ventrolateral-ARC, periventricular and AVPe. PR expression in TH-ir neurones of the periventricular and rostral, dorsomedial, ventrolateral and caudal-ARC decreased transitorily during the afternoon, showing the lowest levels between 14 and 16 h; but it did not vary in the AVPe and VMPO. Plasma oestradiol and progesterone concentrations were low and unaltered during oestrous, indicating that the changes in receptors expression were probably not due to variation in ligand levels. Thus, our data suggest that variations in ER alpha and PR expression may promote changes in the activity of medial basal hypothalamus and POA dopaminergic neurones, even under unaltered secretion of ovarian steroids, which could facilitate the occurrence and modulate the magnitude of the prolactin surge on oestrous.