Chemoreception Mechanisms in Aquatic Animals

在1995年和1996年研究者之间的合作互动中，n。Suzuki， K.Kurihara， J.Caprio, t.v arenincic和T.Marui等人对水生动物，特别是鱼类的化学接受机制有了更好的了解。并对今后的研究方向进行了展望。他们合作的具体成果包括：(1)合作实验提高了硬骨鱼、虹鳟鱼、鳙鱼和鲤鱼分离的嗅觉和味觉受体细胞的产量和活力。鱼类单个嗅觉受体神经元的化学特异性导致了持续的研究，以证实单个嗅觉受体神经元对结合独立受体的多种氨基酸作出反应，并且鱼类的单个受体神经元经常对氨基酸的自发活性产生抑制反应。;(2)通过对大马哈鱼归巢机制的探讨，得出了大马哈鱼对氨基酸的嗅觉反应不受嗅觉器官周围离子环境变化的影响，可以根据河水中不同氨基酸含量的嗅觉线索来辨别归巢河流的结论。;(3)中央“味觉”核内普遍存在对味觉和触觉刺激都敏感的神经元，这表明鲶鱼周围面神经纤维可以只对味觉、只对触觉或同时对味觉和触觉刺激有反应。因此，中枢神经元的双峰性既可以通过味觉纤维和触觉纤维的聚合发生，也可以通过双峰纤维本身发生。奎宁对硬骨鱼味觉系统的抑制作用主要基于对奎宁抗疟疾研究的假设，即对钙通道的阻断作用。;(4)对牛头鲶鱼的嗅觉调节进行了合作实验，结果表明，被单一氨基酸调节的鲶鱼能够将其与其他单一氨基酸区分出来，而二元氨基酸混合物则是通过混合物中生理刺激性更强的成分来区分的。;(5)利用PCR技术克隆了一个可能参与味觉转导的g蛋白cDNA候选序列，并利用DIG探针技术证实了其在鲤鱼鱼刺味觉细胞顶端的表达。少

During collaborative interactions in 1995 & 1996 among the investigators, Drs.N.Suzuki, K.Kurihara, J.Caprio, T.Valentincic and T.Marui, a better understanding of the chemoreception mechanisms in aquatic animals, specifically in fishes was realized. in addition, research directions for future studies were outlined. Specific accomplishments of their collaborative interactions include : (1) Collaborative experiments improved the yield and viability of siolated olfactory and gustatory receptor cells from teleosts, rainbow trout, bullhead catfish and carp. The chemical specificity of single olfactory receptor neurons in fishes resulted in continuing studies to confirm that individual olfactory receptor neurons respond to multiple amino acids that bind to independent receptors, and that single receptor neurons of fish often respond to amino acids wih a suppression of their spontaneous activity. ; (2) Discussions concerning the homing mechanisms of euryharine fishes resulted in a conclusion … More that olfactory responses to amino acids are not influenced by changes in ionic environments surrounding olfactory organs, and that the salmon May discriminate the home river by the olfactory clue based on the content of different amino acids in the river water. ; (3) The pervasiveness of neurons within central "gustatory" nuclei that are sensitive to both taste and tactile stimulation resulted in a conclusion that peripheral facial fibers in the catfish can be responsive to only taste, to only tactile or to both taste and tactile stimulation. Thus, the bimodality of central neurons could occur by either the convergence of taste only and tactile only fibers or by bimodal fibers themselves. The suppressive effects of quinine on teleost taste systems resulted in a hypothesis based primarily on the anti-malarial research on quinine, i.e.a blocking effect on calcium channels. ; (4) Collaborative experiments on olfactory conditionings of bullhead catfish resulted in a conclusion that the catfish conditioned to a single amino acid can discriminate it from other single amino acids, and that binary mixtures of amino acids are discriminated by physiologically more stimulatory component within the mixture. ; (5) A candidate of cDNA for a G-protein that may involve in the taste transduction was cloned with a PCR technique and its expression in the apical part of taste cells of carp barbels was confirmed by using a DIG probe technique. Less