Baines R A, Tyrer N M, Downer R G
Department of Biology, University of Waterloo, Ontario, Canada.
J Comp Neurol. 1990 Apr 22;294(4):623-32. doi: 10.1002/cne.902940409.
The mandibular closer muscles of the locust receive innervation that is immunoreactive for the putative transmitter 5-hydroxytryptamine (5-HT). Cobalt-labelling suggests that the origin of this innervation is a group of cells located anteriorly in the suboesophageal ganglion. Bath application of 5-HT while the muscles are active produces marked changes in the contractions, increasing their amplitude, rate of contraction, and rate of relaxation. Incubation of isolated muscles with 5-HT shows that this amine elevates the levels of the cyclic nucleotide cyclic adenosine monophosphate (cAMP). In addition compounds that artificially elevate the levels of cAMP in the muscle--3-isobutyl-1-methylxanthine (IBMX), forskolin, and the cAMP analogue 8-(4-chlorophenylthio) cAMP--mimic the actions of 5-HT, whereas a potent inhibitor of insect adenylate cyclase, adenosine, considerably delays the onset of the effects produced by 5-HT. The effects observed with 5-HT in the mandibular muscle are similar to those of octopamine in the locust extensor tibiae muscle, and it is possible that this is an analogous modulatory system.
蝗虫的下颌闭合肌接受对假定递质5-羟色胺（5-HT）呈免疫反应的神经支配。钴标记表明，这种神经支配的起源是位于咽下神经节前部的一组细胞。在肌肉活动时浴加5-HT会使收缩产生显著变化，增加其幅度、收缩速率和松弛速率。用5-HT孵育分离的肌肉表明，这种胺会提高环核苷酸环磷酸腺苷（cAMP）的水平。此外，能人为提高肌肉中cAMP水平的化合物——3-异丁基-1-甲基黄嘌呤（IBMX）、福斯可林和cAMP类似物8-（4-氯苯基硫代）cAMP——模拟了5-HT的作用，而昆虫腺苷酸环化酶的强效抑制剂腺苷则大大延迟了5-HT产生的效应的起始时间。在蝗虫下颌肌中观察到的5-HT的作用与在蝗虫胫节伸肌中章鱼胺的作用相似，并且有可能这是一个类似的调节系统。
