利用體外培養的方式探討生物胺對淡水長臂大蝦(Macrobrachium rosenbergii)促血糖生成作用之研究

Abstract

生物胺種類包括多巴(DOPA)、多巴胺(dopamine)、腎上腺素(epinephrine)、正腎上腺素(norepinephrine)、章魚涎胺(Octoamine)及血清動素(serotonin)等等，在甲殼類神經系統的分佈相當廣泛，所扮演的角色為神經傳導物(Neurotransmitter)及神經調節物(Neuroregulator)在生理的調控上具有多方面之功能，例如，調節呼吸、心跳速率，血糖、滲透壓之調整，甲殼之硬化作用，體色改變，組織修復，以及免疫反應等，甚至在行為方面也扮演著重要的角色。 動物個體必須消耗能量以為維持自身之生存、成長、生殖等生理機能，而葡萄糖即扮演著主要能量供應者的角色，因此血糖值可作為反應生理狀況之生理指標。本研究以淡水長臂大蝦(Macrobrachium rosenbergii)實驗材料，探討正腎上腺素(NE)、腎上腺素(E)、多巴胺(DA)血清動素(5-HT)四種生物胺對血糖之調節作用、作用途徑及作用受器。 為了釐清淡水長臂大蝦之血糖調控方式，本研究以淡水長臂大蝦肝胰臟及肌肉組織進行體外培養，利用NE、E、DA、5-HT進行外源刺激，藥劑處理後兩小時進行採樣，並更換培養基，追加生物胺使之維持固定實驗濃度。檢測追蹤樣品中葡萄糖含量變化，研究結果發現四種生物胺皆會促進肝胰臟及肌肉組織之葡萄糖釋放能力，並顯示該四種生物胺對於血糖之促進作用是不需透過眼柄中X-器官竇腺複合體(X-Organ sinus gland complex)所分泌之CHH，亦證實肝胰臟組織為淡水長臂大蝦之主要血糖供應組織。 在生物胺配合不同型接受器(receptors)之拮抗劑之處理中，發現正腎上腺素之作用受器為α1及βl，、腎上腺素之作用受器為α1其次為βl，多巴胺之主要作用受器為D1，血清動素之主要作用受器為5HT 2。此部份實驗純粹為藥理性研究，所使用受器拮抗劑皆研發自哺乳類動物，而甲殼類生物與哺乳類動物間之生物胺作用受器是否具有高度之相似性，對拮抗劑之親和力是否雷同等等，仍須進一步之研究。

Biogenic amines, dopa, dopamine, norepinephrine, epinephrine, octopamine, serotonin, and others, are widely distributed in the neural system and ganglia of crustaceans. They, as neurotransmitters and neuroregulators, are involved in regulating a wide spectrum of important physiological processes in organisms. Included are respiratory regulation, heart beating, glycemia, osmoregulation, hardening of exoskeleton, body coloration, immune and behavioral responses as well. The physiological homeostasis and homeokinesis of animals are maintained through constant physiological compensation and regulation, which depend heavily on the sufficient supply of energy. Glucose, generally considered as an important energy sources in a variety of organisms and is frequently used as a biological indicator of the physiological conditions. The objectives of the present research are aimed to clarify the modes and pathways of the actions of norepinephrine, epinephrine, dopamine and serotonin in the glycemic responses of Macrobrachium rosenbergii in vitro. The goal is approached by incubation of the hepatopancreas tissue with biogenic amine alone or with the combination of biogenic amine and its specific receptor antagonists, and the responses were monitored by quantifying the glucose content in the culture medium at 2 hr intervals. The culture medium and biogenic amines experimented are replenished at the same time. The results revealed that all the biogenic amines examined in this study, do enhance the glucose release from the hepatopancreas and muscular tissues. This suggests that the hyperglycemic response is not necessarily mediated through the actions of CIIH, secreted and released from x-organ sinus gland complex. In the meantime, the hepatopancreas can be considered to be more important for the source of energy supply, when the glucose released at a specific dose is compared. In addition, the pathways of the actions of the biogenic amines is summaried as follows: the actions is mediated through αl and β1 for norepinephrine and epinephrine , and through D1 and 5-HT2 for dopamine and 5-HT , respectively , The pharmacological research strategies were followed in this study , and the antagonists employed were all developed in mammals . The homology of the receptors of NE, E, DA and 5-HT, and the affinity of antagonists to various receptors between the freshwater giant prawn and mammals are still unknown and remained for further elucidation.