Duve H, Thorpe A
School of Biological Sciences, Queen Mary College, London University, United Kingdom.
Cell Tissue Res. 1989 Oct;258(1):147-61. doi: 10.1007/BF00223154.
Neuronal pathways immunoreactive to antisera against the extended-enkephalins, Met-enkephalin-Arg6-Phe7 (Met-7) and Met-enkephalin-Arg6-Gly7-Leu8 (Met-8), have been identified in the brain of the blowfly Calliphora vomitoria. Co-localisation with other enkephalins in certain neurons suggests that a precursor similar to preproenkephalin A exists in insects and that differential enzymatic processing occurs as in vertebrates. Co-localisations of the extended-enkephalin-like peptides with other vertebrate-type peptides, including cholecystokinin and pancreatic polypeptide, also occur. The enkephalinergic pathways are specific, comprising a few groups of highly characteristic neurons and areas of neuropil. Of special interest is the finding that parts of the antennal chemosensory and the optic lobe visual systems contain Met-8 immunoreactive neurons. Within the median neurosecretory cell groups, some of the giant neurons show immunoreactivity to Met-8 and others to both Met-8 and Met-7. Fibres from these cells project to the corpus cardiacum and also to the suboesophageal ganglion, where arborisations occur in the tritocerebral neuropil. Co-localisation studies of these cells have shown that at certain terminals, one particular type of peptide is the dominant neuroregulator, whilst at other terminals, within the same cell, a different co-synthesised peptide predominates. Several groups of lateral neurosecretory cells show clearly defined enkephalinergic pathways, most of which have connections with the central body. The complex patterns of immunoreactivity seen in terminals in the different parts of the central body, suggest an important role for the enkephalin-like peptides in the integration of multimodal sensory inputs. The physiological functions of the extended-enkephalin-like peptides in the brain of Calliphora is still unknown, but the anatomical evidence suggests they may have a role similar to that in mammals, where they are thought to control aspects of feeding behaviour.
在丽蝇（Calliphora vomitoria）的大脑中，已鉴定出对针对延伸脑啡肽、甲硫氨酸脑啡肽-精氨酸6-苯丙氨酸7（Met-7）和甲硫氨酸脑啡肽-精氨酸6-甘氨酸7-亮氨酸8（Met-8）的抗血清具有免疫反应性的神经通路。在某些神经元中与其他脑啡肽的共定位表明，昆虫中存在一种类似于前脑啡肽原A的前体，并且与脊椎动物一样发生了差异性酶促加工。延伸脑啡肽样肽与其他脊椎动物型肽（包括胆囊收缩素和胰多肽）也存在共定位。脑啡肽能通路是特异性的，由几组具有高度特征性的神经元和神经纤维网区域组成。特别有趣的是发现触角化学感觉系统和视叶视觉系统的部分区域含有Met-8免疫反应性神经元。在中位神经分泌细胞群中，一些巨型神经元对Met-8有免疫反应性，而其他一些对Met-8和Met-7都有免疫反应性。来自这些细胞的纤维投射到心侧体，也投射到咽下神经节，在那里树突分支出现在后脑神经纤维网中。对这些细胞的共定位研究表明，在某些终末，一种特定类型的肽是主要的神经调节剂，而在同一细胞内的其他终末，另一种共同合成的肽占主导地位。几组外侧神经分泌细胞显示出明确的脑啡肽能通路，其中大多数与中央体有连接。在中央体不同部位的终末中看到的复杂免疫反应模式表明，脑啡肽样肽在多模式感觉输入的整合中起重要作用。丽蝇大脑中延伸脑啡肽样肽的生理功能仍然未知，但解剖学证据表明它们可能具有与哺乳动物中类似的作用，在哺乳动物中它们被认为控制进食行为的各个方面。
