Blasquez C, Jégou S, Friard O, Tonon M C, Fournier A, Vaudry H
European Institute for Peptide Research, INSERM U 413, UA CNRS, University of Rouen, Mont-Saint-Aignan, France.
Neuroscience. 1995 Sep;68(1):221-7. doi: 10.1016/0306-4522(95)00119-4.
In a previous study, we have shown that neuropeptide Y inhibits the release of alpha-melanocyte-stimulating hormone from the rat hypothalamus in vitro. The aim of the present study was to investigate the possible effect of neuropeptide Y on the regulation of proopiomelanocortin-derived peptides in vivo. Rats received acute or chronic administration of neuropeptide Y in the lateral ventricle and the amount of alpha-melanocyte-stimulating hormone was measured in the hypothalamus and in the neurointermediate lobe of the pituitary. In the same experiments, the amounts of corticotropin-releasing factor and corticotropin were quantified in the hypothalamus and anterior pituitary, respectively. Acute treatment with synthetic neuropeptide Y (0.1 to 10 micrograms/rat) did not modify the amount of alpha-melanocyte-stimulating hormone in the hypothalamus. In contrast, chronic infusion of neuropeptide Y (1.25 micrograms/h) over a seven day period significantly decreased the hypothalamic content of alpha-melanocyte-stimulating hormone, suggesting that neuropeptide Y regulates the synthesis and/or the processing of proopiomelanocortin. Concurrently, we found that both acute and chronic infusion of neuropeptide Y induced a significant reduction in corticotropin-releasing factor in the hypothalamus as well as a significant decrease in alpha-melanocyte-stimulating hormone and corticotropin in the neurointermediate and anterior lobes, respectively. Quantitative in situ hybridization histochemistry showed that chronic administration of neuropeptide Y also caused a reduction of proopiomelanocortin messenger RNA levels both in the intermediate and anterior lobes of the pituitary. Administration of neuropeptide Y (10(-6) M) on perifused rat hypothalamic slices caused a significant increase in corticotropin-releasing factor release.(ABSTRACT TRUNCATED AT 250 WORDS)
在之前的一项研究中，我们已表明神经肽Y在体外可抑制大鼠下丘脑释放α-促黑素细胞激素。本研究的目的是探讨神经肽Y在体内对阿黑皮素原衍生肽调节的可能作用。给大鼠侧脑室内急性或慢性注射神经肽Y，然后测定下丘脑及垂体神经中间叶中α-促黑素细胞激素的含量。在相同实验中，分别对下丘脑和垂体前叶中的促肾上腺皮质激素释放因子及促肾上腺皮质激素进行定量。用合成神经肽Y（0.1至10微克/只大鼠）进行急性处理，并未改变下丘脑内α-促黑素细胞激素的含量。相反，在7天时间内慢性输注神经肽Y（1.25微克/小时）显著降低了下丘脑内α-促黑素细胞激素的含量，这表明神经肽Y调节阿黑皮素原的合成和/或加工过程。同时，我们发现急性和慢性输注神经肽Y均导致下丘脑促肾上腺皮质激素释放因子显著减少，以及神经中间叶和垂体前叶中α-促黑素细胞激素和促肾上腺皮质激素分别显著降低。定量原位杂交组织化学显示，慢性给予神经肽Y还导致垂体中间叶和前叶中阿黑皮素原信使核糖核酸水平降低。给灌流的大鼠下丘脑切片施用神经肽Y（10⁻⁶ M）导致促肾上腺皮质激素释放因子释放显著增加。（摘要截短于250词）
