Université de Bordeaux, CNIC UMR 5228 CNRS, Talence, France.
Insect Biochem Mol Biol. 2009 Nov;39(11):755-62. doi: 10.1016/j.ibmb.2009.09.008. Epub 2009 Oct 6.
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.
最初在美洲大蠊中发现的十肽神经肽 corazonin 是一种强烈的心脏加速剂，现在已知它广泛存在于节肢动物中，尽管它不存在于某些物种中，特别是鞘翅目。其前体的结构与 GnRH 前体相似，而它通过与 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。它由脑内的神经内分泌细胞以及腹神经索中的中间神经元产生。这两种细胞类型通常存在于昆虫中；在大多数物种中，还有其他产生 corazonin 的神经元。它在昆虫中的功能仍然不清楚；它的心脏加速作用仅限于少数几种蟑螂物种，而在其他物种中，已经描述了不同的生理作用。最引人注目的是，它诱导了群居阶段的变化，在迁徙性蝗虫中，它还减少了形成的茧的大小。corazonin 能够诱导两种蛾类蜕皮，然而，corazonin 基因不再表达的蝗虫和苍蝇正常蜕皮，因此，尚不清楚 corazonin 是否对蜕皮至关重要。由于脑中的 corazonin 神经内分泌细胞表达两种中肠肽的受体，因此它们的活性似乎可能被中肠内分泌细胞调节。我提出，在昆虫中，corazonin 可能在营养胁迫下释放，这可以解释这种神经激素的几种观察到的生理作用。
