HPLC ANALYSIS OF NEUROTRANSMITIERS IN THE CARDIAC NERVOUS SYSTEM OF CRUSTACEANS

已知甲壳类具有神经性心脏，其心肌细胞在心脏神经节节律活动神经元的严格控制下收缩。我们先前已经证明，斑点叉尾轮虫的心肌对谷氨酸敏感。在药理实验中，谷氨酸、奎尼酸和红藻氨酸以剂量依赖的方式增加心肌细胞的张力。剂量-反应关系显示，EC50约为10-4M准分子，约3×10-4M谷氨酸，约5×10-4M海人藻酸盐。因此，效力的顺序是合格的&>谷氨酸>>海人酸。采用高效液相色谱(HPL C)技术分析了弹尾藻(Bathynomus)心脏神经节和心肌提取物中的谷氨酸。谷氨酸含量分别为8741.2+/-184.2pmol/mg和678.2+/-10.7pmol/mg。目前的研究可能表明，心脏神经节中的运动神经元是谷氨酸。长期以来，人们一直在重复，乙酰胆碱加速十足类甲壳类动物的心脏。Yazawa和Kuwa awa(1992)最近提出，乙酰胆碱是寄居蟹心脏神经节小神经元神经递质的主要候选者。我们进行了高效液相分析(与电化学检测)的心脏神经节，并检测到乙酰胆碱在这两种动物的心脏神经节。我们分析了美洲血吸虫心脏神经节中的乙酰胆碱含量。为129±-3.2fmol/mg湿重。本研究支持先前的假设(Yazawa和Kuwaawa，1992)。我们认为十足甲壳动物心脏神经节中的小神经元可能是胆碱能神经元，因为神经节中的其他神经元和神经元突起是多巴胺和GABA能的(Yazawa和Kuwa awa，1992,1994)。

It is known that crustaceans have the neurogenic heart whose myocardial cells contract under tight control of rhythmically active neurons in the cardiac ganglion. We have previously demonstrated that myocardium of Bathynomus doederleini was sensitive to glutamate. In pharmacological tests, glutamate, quisqualate and kainate developed tension of myocardial cells in a dose-dependent manner. The dose-response relationship showed an EC50 of about 10-4 M quisqualate, about 3*10-4 M glutamate, and about 5*10-4 M kainate. The order of potency was thus quisqualate>glutamate>kainate. We analyzed glutamate in the extracts of the cardiac ganglion and myocardium of the Bathynomus by means of a technique, high performance liquid chromatography (HPLC). The analysis revealed, respectively, 8741.2+/-184.2pmol/mg and 678.2+/-10.7 pmol/mg for glutamate contents. The present study may show that motor neurons in the cardiac ganglion are glutamatergic.It has long been repeated that acetylcholine accelerates the heart of decapod crustaceans. Yazawa and Kuwasawa (1992) recently suggested that acetylcholine is the primary candidate for a neurotransmitter of small neurons in the cardiac ganglion of the hermit crab, Aniculus aniculus. We performed a HPLC analysis (with electrochemical detection) of the cardiac ganglion of A.aniculus and Homarus americanus, and detected acetylcholine in the cardiac ganglia of both the animals. We analyzed acetylcholine content in the cardiac ganglia of H.americanus. It was 129+-3.2 fmol/mg wet weight. The present study support the previous postulation (Yazawa and Kuwasawa, 1992) . We conclude that the small neurons in the cardiac ganglion of decapod crustaceans may be cholinergic nerurons, since other neurons and neuronal processes in the ganglion are revealed to be dopaminergic and GABAergic (Yazawa and Kuwasawa, 1992,1994).