Does corazonin signal nutritional stress in insects?
Does corazonin signal nutritional stress in insects?
复制标题
DOI：
10.1016/j.ibmb.2009.09.008
复制
发表时间：
2009-11
影响因子：
3.8
通讯作者：
J. Veenstra
中科院分区：
文献类型：
--
作者：
J. Veenstra
非肽类corazonin最初是作为一种强大的心脏加速器从美洲蟑螂中发现的，现在已知它普遍存在于节肢动物中，尽管它在某些物种中不存在，尤其是鞘翅目。其前体结构与GnRH前体相似，但通过与GnRH受体相关的受体起作用；因此，corazonin似乎是GnRH的节肢动物同源物。它是由大脑中的神经内分泌细胞以及腹侧神经索的中间神经元产生的。这两种细胞类型通常存在于昆虫中；在大多数物种中，也有其他神经元产生corazonin。它在昆虫中的作用仍然不清楚；它的心脏加速作用仅限于少数蟑螂物种，而在其他物种中有不同的生理作用。最引人注目的是，它引起了与迁徙的蝗虫和蚕的群居期有关的变化，它减少了形成的茧的大小。Corazonin能够在两种蛾类中诱导蜕皮，然而，在Corazonin基因不再表达的蝗虫和苍蝇中，蜕皮正常，因此，尚不清楚Corazonin是否是蜕皮所必需的。由于脑内corazonin神经内分泌细胞表达两种中肠肽受体，它们的活性可能受到中肠内分泌细胞的调节。我认为，在昆虫体内，corazonin可能在营养紧张的条件下被释放，这可以解释这种神经激素的几种观察到的生理效应。
The undecapeptide corazonin, initially discovered from the American cockroach as a strong cardioaccelerator, is now known to be ubiquitously present in arthropods, although it is absent from some species, notably Coleoptera. The structure of its precursor is similar to the GnRH precursor, while it acts through a receptor related to the GnRH receptor; corazonin thus appears to be an arthropod homolog of GnRH. It is produced by neuroendocrine cells in the brain, as well as interneurons in the ventral nerve cord. These two cell types are generally present in insects; in most species there are also other neurons producing corazonin. Its function in insects has remained obscure; its cardioacceleratory effects are limited to a few cockroach species, while in other species different physiological effects have been described. Most spectacularly it induces changes associated with the gregarious phase in migratory locusts and in the silkworm it reduces the size of the cocoon formed. Corazonin is able to induce ecdysis in two moth species, however locusts and flies in which the corazonin gene is no longer expressed, ecdyse normally and, hence, it is not clear whether corazonin is essential for ecdysis. As the corazonin neuroendocrine cells in the brain express receptors for two midgut peptides, it seems likely that their activity is modulated by the midgut endocrine cells. I propose that in insects corazonin might be released under conditions of nutritional stress, which can explain several of the observed physiological effects of this neurohormone.