LOCALIZATION OF NEUROPEPTIDE-Y IMMUNOREACTIVITY IN ESTRADIOL-CONCENTRATING CELLS IN THE HYPOTHALAMUS
LOCALIZATION OF NEUROPEPTIDE-Y IMMUNOREACTIVITY IN ESTRADIOL-CONCENTRATING CELLS IN THE HYPOTHALAMUS
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DOI：
10.1210/endo-127-6-2752
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发表时间：
1990-12-01
期刊：
影响因子：
4.8
通讯作者：
KALRA, SP
中科院分区：
文献类型：
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作者：
SAR, M;SAHU, A;KALRA, SP
大量证据表明，性腺类固醇对下丘脑神经肽-Y(NPY)的水平和释放有易化影响。然而，目前尚不清楚性腺激素是否直接作用于下丘脑弓状核(ARC)中产生NPY的细胞，从而对NPY产生这些易化作用，或者它们是否作用于通过突触对ARC NPY细胞产生调制影响的其他细胞。我们应用类固醇放射自显影和免疫细胞化学相结合的方法来评估[~3H]雌二醇在下丘脑中的定位与NPY产生细胞的关系。大鼠(n=6)双侧卵巢切除后脑室注射秋水仙碱。24小时后，每只大鼠静脉注射17β-[2，4，6，7，16，17-3H]雌二醇(SA，166Ci/mmo1)，剂量为5.0ug/kg bw。注射[~3H]雌二醇1h后，用4%多聚甲醛灌流大鼠，取出脑组织，在液氮(-190℃)中预冷的异戊烷中冷冻，切片，进行放射自显影。然后将放射自显影与NPY特异性抗体孵育，用亲和素-生物素-过氧化物酶方法进行NPY免疫染色。结果显示，在弓状核、纹状体、海马体、杏仁核和大脑皮质有NPY免疫阳性细胞，在正中隆起有少量细胞。正中隆起内层也可见NPY免疫反应纤维。胞浆内NPY免疫反应阳性神经元最多的是弓状核，只有在这个核团才观察到雌二醇和NPY免疫阳性神经元共存。ARC内有一群NPY免疫阳性细胞(10-20%)显示有核的[~3H]雌二醇核，这些细胞大多位于ARC的外侧和腹侧。由于性腺激素刺激下丘脑NPY水平和释放，这种共同定位的解剖学证据表明，类固醇对下丘脑NPY免疫阳性神经元亚群的NPY神经分泌有直接的基因组调节作用。
Considerable evidence shows that gonadal steroids exert a facilitatory influence on levels and release of neuropeptide-Y (NPY) from the hypothalamus. However, it is not known whether gonadal steroids act directly on NPY-producing cells in the arcuate nucleus (ARC) of the hypothalamus to produce these facilitatory effects on NPY or whether they act on other cells that have a modulatory influence via synapses on ARC NPY cells. We applied the combined method of steroid autoradiography and immunocytochemistry to assess the localization of [3H]estradiol in relation to NPY-producing cells in the hypothalamus. Rats (n=6) were bilaterally ovariectomized and injected intracerebroventricularly with colchicine. Twenty-four hours later each rat received an iv injection of 17.beta.-[2,4,6,7,16,17-3H]estradiol (SA, 166 Ci/mmol) at a dose of 5.0 .mu.g/kg BW. One hour after the injection of [3H]estradiol, the rats were perfused with 4% paraformaldehyde; brains were removed, frozen in isopentane precooled in liquid nitrogen (-190 C), sectioned, and processed for autoradiography. The autoradiograms were then incubated with specific antibodies for NPY immunostaining by the avidin-biotin-peroxidase method. The results revealed NPY-immunopositive cells in the ARC, striatum, hippocampus, amygdala, and cerebral cortex and a few cells in the median eminence. NPY-immunoreactive fibers were also detected in the internal layer of the median eminence. The largest number of neurons showing NPY immunoreactivity in the cytoplasm was detected in the ARC, and only in this nucleus did we observe colocalization of [3H.degree.)estradiol and NPY immunoreactivity in neurons. A population of NPY-immunopositive cells in the ARC (10-20%) exhibited nuclear [3H]estradiol; the majority of these cells were located in the lateral and ventral portions of the ARC. Since gonadal steroids stimulate hypothalamic NPY levels and release, this anatomical evidence of colocalization is suggestive of a direct genomic modulation of NPY neurosecretion by steroids in a subpopulation of hypothalamic NPY-immunopositive neurons.