HPLC ANALYSIS OF NEUROTRANSMITIERS IN THE CARDIAC NERVOUS SYSTEM OF CRUSTACEANS

已知甲壳类动物具有神经源性心脏，其心肌细胞在心脏神经节中节律性活性神经元的严格控制下收缩。我们以前已经证明，心肌的Bathynomus doederleini是敏感的谷氨酸。药理实验表明，谷氨酸、使君子酸和红藻氨酸均能引起心肌细胞张力增加，且呈剂量依赖性。剂量-反应关系显示EC 50约为10-4 M使君子酸盐、约3*10-4 M谷氨酸盐和约5*10-4 M红藻氨酸盐。因此，效力的顺序为使君子酸>谷氨酸>红藻氨酸。我们分析了谷氨酸的提取物的心神经节和心肌的Bathynomus通过一种技术，高效液相色谱法（HPLC）。分析显示，谷氨酸含量分别为8741.2+/-184.2pmol/mg和678.2+/-10.7 pmol/mg。本研究可能表明，心神经节的运动神经元是乙酰胆碱能的。乙酰胆碱加速十足类甲壳动物心脏的作用早已被证实。Yazawa和Kuwasawa（1992）最近提出，乙酰胆碱是寄居蟹（Aniculus aniculus）心脏神经节中小神经元的神经递质的主要候选者。我们进行了HPLC分析（电化学检测）的心神经节的A.aniculus和Homarus americanus，并检测到乙酰胆碱在这两种动物的心神经节。我们分析了乙酰胆碱含量在心脏神经节的H. americanus。其为129 ± 3.2 fmol/mg湿重。目前的研究支持以前的假设（Yazawa和Kuwasawa，1992）。我们的结论是，在十足类甲壳动物的心神经节的小神经元可能是胆碱能神经元，因为在神经节中的其他神经元和神经元过程被揭示为多巴胺能和GABA能（Yazawa和Kuwasawa，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).