Evans P D, Kravitz E A, Talamo B R, Wallace B G
J Physiol. 1976 Oct;262(1):51-70. doi: 10.1113/jphysiol.1976.sp011585.
Octapamine and its synthetic enzyme, tyramine beta-hydroxylase (TBH), are found in high concentrations at two points along second thoracic nerve roots in lobsters. The first is in the proximal section of the second root between the ventral nerve cord and the bifurcation of the root into medial (to flexor muscles) and lateral (to extensors) branches. The second region of high concentration is within a well known crustacean neurosecretory system, the pericardial organ, located close to the ends of the lateral branches of the roots. 2. With several different staining procedures, small clusters of nerve cell bodies are found within the connective tissue sheath in the proximal regions of the second roots. No cell bodies are seen in the pericardial organ regions. Cell bodies are variable in number and position between corresponding roots in the same animal and homologous roots among different animals. The average numbers of cell bodies, however, correlate well with TBH and octopamine content, and with the synthesis of octopamine in these same regions of roots. 3. Small clusters of root cell bodies dissected from preparations have greater than 500-fold higher activities of TBH than isolated efferent excitatory and inhibitory or afferent sensory axons. 4. Along with octopamine, the preferential synthesis of acetylcholine and serotonin is also seen in proximal segments of roots. Acetylcholine synthesis in these regions may represent transmitter synthesized in the nerve terminals innervating the root cells. The role of serotonin in these regions is not understood at this time but the amounts of endogenous serotonin found are only a tenth of the amounts of octopamine present. 5. Dopamine is not synthesized from tyrosine in second thoracic roots. However, if DOPA or dopamine are used as precursor compounds, then noradrenaline, which is usually not found in lobsters, can be accumulated in proximal segments of roots. 6. Phenolamines are converted to two further metabolites by lobster tissues. The compounds are unidentified and are named fast and slow product on the basis of their migration on electrophoresis at acid pH. Some partial characterization of slow product reveals that it is a mixture of compounds that can be converted on mild acid hydrolysis to fast product and the parent phenolamine. 7. The several lines of evidence presented suggest that nerve cells found in the proximal segments of the second thoracic roots contain and can synthesize octopamine. Since not all the cells in any single root have been analysed for octopamine or TBH, however, the possibility that one or more of the cells contain physiologically interesting substances other than octopamine is not eliminated.
章鱼胺及其合成酶——酪胺β-羟化酶（TBH），在龙虾第二胸神经根沿线的两个部位浓度很高。第一个部位在第二神经根的近端，位于腹神经索与神经根分为内侧（至屈肌）和外侧（至伸肌）分支的分叉点之间。第二个高浓度区域位于一个著名的甲壳类神经分泌系统——围心器官内，该器官靠近神经根外侧分支的末端。2. 通过几种不同的染色方法，在第二神经根近端区域的结缔组织鞘内发现了小簇神经细胞体。在围心器官区域未观察到细胞体。同一动物相应神经根之间以及不同动物同源神经根之间，细胞体的数量和位置各不相同。然而，细胞体的平均数量与TBH和章鱼胺含量以及这些相同神经根区域中章鱼胺的合成密切相关。3. 从制备物中分离出的小簇根细胞体的TBH活性比分离出的传出兴奋性和抑制性或传入感觉轴突高500倍以上。4. 除了章鱼胺外，在神经根近端段还可见乙酰胆碱和5-羟色胺的优先合成。这些区域的乙酰胆碱合成可能代表在支配根细胞的神经末梢中合成的神经递质。目前尚不清楚5-羟色胺在这些区域的作用，但所发现的内源性5-羟色胺量仅为章鱼胺量的十分之一。5. 第二胸神经根中酪氨酸不合成多巴胺。然而，如果使用多巴或多巴胺作为前体化合物，那么通常在龙虾中不存在的去甲肾上腺素可以在神经根近端段积累。6. 酚胺被龙虾组织进一步转化为另外两种代谢产物。这些化合物尚未鉴定，根据它们在酸性pH下电泳时的迁移情况分别命名为快速产物和慢速产物。对慢速产物的一些部分表征表明，它是一种化合物混合物，在温和酸性水解下可转化为快速产物和母体酚胺。7. 所提供的几条证据表明，在第二胸神经根近端段发现的神经细胞含有并能合成章鱼胺。然而，由于尚未对任何单个神经根中的所有细胞进行章鱼胺或TBH分析，因此不能排除一个或多个细胞含有除章鱼胺之外的具有生理意义物质的可能性。
