Laboratories of Cellular and Developmental Biology, Stazione Zoologica Anton Dohrn, 80121 Naples, Italy.
J Biol Chem. 2010 Jul 30;285(31):24154-63. doi: 10.1074/jbc.M109.083428. Epub 2010 Jun 1.
Chromatophore organs are complex and unique structures responsible for the variety of body coloration patterns used by cephalopods to communicate and camouflage. They are formed by a pigment-containing cytoelastic sacculus, surrounded by muscle fibers directly innervated from the brain. Muscle contraction and relaxation are responsible for expansion and retraction of the pigment-containing cell. Their functioning depends on glutamate and Phe-Met-Arg-Phe-NH(2)-related peptides, which induce fast and slow cell expansion, respectively, and 5-hydroxytryptamine, which induces retraction. Apart from these three substances and acetylcholine, which acts presynaptically, no other neuroactive compounds have so far been found to be involved in the neuroregulation of chromatophore physiology, and the detailed signaling mechanisms are still little understood. Herein, we disclose the role of nitric oxide (NO) as mediator in one of the signaling pathways by which glutamate activates body patterning. NO and nitric-oxide synthase have been detected in pigment and muscle fibers of embryo, juvenile, and adult chromatophore organs from Sepia officinalis. NO-mediated Sepia chromatophore expansion operates at slower rate than glutamate and involves cGMP, cyclic ADP-ribose, and ryanodine receptor activation. These results demonstrate for the first time that NO is an important messenger in the long term maintenance of the body coloration patterns in Sepia.
色素器官是复杂而独特的结构，负责头足类动物用于交流和伪装的各种身体颜色图案。它们由含有色素的细胞弹性囊组成，周围是直接由大脑神经支配的肌肉纤维。肌肉的收缩和松弛负责含色素细胞的扩张和收缩。它们的功能取决于谷氨酸和 Phe-Met-Arg-Phe-NH(2)-相关肽，分别诱导快速和缓慢的细胞扩张，5-羟色胺诱导收缩。除了这三种物质和乙酰胆碱（作为突触前物质起作用）之外，目前尚未发现其他神经活性化合物参与色素生理学的神经调节，详细的信号机制仍知之甚少。在此，我们揭示了一氧化氮（NO）作为介导物在谷氨酸激活身体图案形成的信号通路之一中的作用。NO 和一氧化氮合酶已在乌贼胚胎、幼年和成年色素器官的色素和肌肉纤维中检测到。NO 介导的乌贼色素扩张的速度比谷氨酸慢，涉及 cGMP、环 ADP-核糖和兰尼碱受体的激活。这些结果首次表明，NO 是乌贼身体颜色模式长期维持的重要信使。
