Volkoff Hélène
Departments of Biology and Biochemistry, Memorial University of Newfoundland, St. John's, NL A1B 3X9 Canada.
Peptides. 2014 Nov;61:61-8. doi: 10.1016/j.peptides.2014.09.002. Epub 2014 Sep 9.
Orexins, apelin, melanin-concentrating hormone (MCH), neuropeptide Y (NPY) and cocaine and amphetamine regulated transcript (CART) are important appetite-regulating factors produced by the brain of both mammals and fish. These peptide systems and their target areas are widely distributed within the central nervous system. Although morphological connections between some of these systems have been demonstrated in the brain, little is known about the functional interactions between these systems, in particular in fish. In order to better understand the interactions between appetite-related peptides, the effects of in vitro treatments of hindbrain, forebrain and hypothalamus--a major feeding regulating area--fragments with MCH, apelin and orexin on the expression of MCH, apelin, orexin, CART (forms 1 and 2) and NPY were assessed. Overall, the apelin and orexin systems stimulate each other and stimulate the NPY system while inhibiting the CART system, which is consistent with the known orexigenic actions of these two peptides. The actions of MCH remain unclear: although it appears to interact positively with orexigenic systems--as it stimulates both the orexin and apelin systems and its expression is increased by apelin--it also increases the hypothalamic expression of CART2--but not CART1--an anorexigenic factor, and inhibits the NPY system in all brain regions examined. This study suggests that MCH, apelin, orexin, CART and NPY do influence each other within the brain of goldfish and that these interactions might differ in nature and strength according to the peptide form and the brain region considered.
食欲素、阿片肽、促黑素（MCH）、神经肽Y（NPY）以及可卡因和苯丙胺调节转录物（CART）是哺乳动物和鱼类大脑产生的重要食欲调节因子。这些肽系统及其靶区广泛分布于中枢神经系统内。尽管这些系统中的一些在大脑中的形态学联系已得到证实，但对于这些系统之间的功能相互作用，尤其是在鱼类中的功能相互作用，人们了解甚少。为了更好地理解食欲相关肽之间的相互作用，评估了用MCH、阿片肽和食欲素对后脑、前脑和下丘脑（一个主要的摄食调节区域）片段进行体外处理后，对MCH、阿片肽、食欲素、CART（1型和2型）和NPY表达的影响。总体而言，阿片肽和食欲素系统相互刺激并刺激NPY系统，同时抑制CART系统，这与这两种肽已知的促食欲作用一致。MCH的作用仍不清楚：尽管它似乎与促食欲系统呈正相互作用——因为它刺激食欲素和阿片肽系统，且其表达受阿片肽上调——但它也增加了厌食因子CART2（而非CART1）在下丘脑的表达，并在所有检测的脑区抑制NPY系统。这项研究表明，MCH, 阿片肽、食欲素、CART和NPY在金鱼大脑中确实相互影响，并且这些相互作用可能因肽的形式和所考虑的脑区不同而在性质和强度上有所差异。
