軟絲與烏賊體色改變的週邊神經調控

Peripheral neural control of body patterning in oval squids and cuttlefish

施秉宏(Shih, Bing Hong)

指導教授 ： 焦傳金

國立清華大學/生命科學院/系統神經科學研究所/碩士(2016年)

摘要

現代頭足類能夠以快速改變體色來進行溝通及偽裝。此改變體色的能力主要是藉由神經對皮膚內的色素細胞直接進行控制來達成。目前在中樞神經系統中對色素細胞進行調控的神經傳導路徑已經被廣泛研究，然而在週邊神經系統的體色表現調控方式卻仍屬未知。藉由給予萊氏擬烏賊表皮L-麩胺酸、乙醯膽鹼、血清素、AMPA及NMDA，並觀察色素細胞的擴張與收縮，本研究證實由於環狀肌肉上AMPA受器及NMDA受器表現量的不同，因此可以藉由突觸後作用機制來分別調控黃色及棕色色素細胞的擴張，此外乙醯膽鹼則參與在兩種不同色素細胞調控的突觸前調節機制。在另外一項研究中則以虎斑烏賊為對象觀察色素調控系統的週邊神經發育，藉由觀察皮膚對L-麩胺酸與血清素的反應，本研究顯示色素細胞在胚胎發育至第26期後才會具有功能。而比較不同發育期的胚胎在三種不同方格背景(小方格低對比、小方格高對比、大方格高對比)的體色反應後發現，胚胎雖然在第27期之後可以對環境反應出破碎型體色，然而其色素細胞調控系統卻仍未發展完全以至於不能針對環境差異做出適當反應。綜合以上發現，本研究顯示體色調控的週邊神經系統發育較早，且同時具有突觸前及突觸後兩種調控色素細胞的作用機制。

關鍵字

色素調控系統 ； 週邊神經系統 ； 體色改變

並列摘要

Coleoid cephalopods are well known for their ability to rapidly change body patterns for communication and camouflage. This is primarily achieved by neural control of chromatophores in the skin. The neural connection of the chromatophore system in the central nervous system has been well studied. However, the specific mechanism of the peripheral neural control of chromatophores remains unknown. To determine the mechanism of the peripheral pathway, the several neurotransmitters such as L-Glutamate (L-Glu), serotonin, acetylcholine (ACh), AMPA, and NMDA were applied to the skin of oval squids (Sepioteuthis lessoniana) in vivo and the corresponding chromatophore expansion and retraction were recorded. The results showed that AMPA- and NMDA-like receptors expressed on radial muscles are involved in a postsynaptic mechanism to differentially control yellow and brown chromatophore expansions, and ACh is involved in a presynaptic mechanism of chromatophore control. In a separate study, cuttlefish embryos (Sepia pharaonis) were used to examine the peripheral development of the chromatophore system. The results showed that chromatophores are functional at embryonic stage 26 as evidence of its response to L-Glu and serotonin applications in vitro. In addition, three different checkboard backgrounds (small low-contrast, small high-contrast, and large high-contrast) were used to examine cuttlefish embryo’s ability of body patterning development. The results showed that cuttlefish could express some disruptive components at stage 27, though the full function of body pattern control was not developed completely before hatching. Taken together, this study suggests that the peripheral neural control of the chromatophore system develops early and is regulated by both pre- and post-synaptic mechanisms with various neurotransmitters.

並列關鍵字

chromatophore system ； peripheral neural system ； body patterning

參考文獻

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