Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Kagawa, Japan.
Comp Biochem Physiol B Biochem Mol Biol. 2011 Oct;160(2-3):89-93. doi: 10.1016/j.cbpb.2011.06.007. Epub 2011 Jul 3.
The tripeptide Asn-d-Trp-Phe-NH(2) (NdWFamide) is a D-amino acid-containing cardioexcitatory peptide initially isolated from Aplysia. Previously we detected NdWFamide immunoreactivity in the visceral giant cells, the largest neurons in the brain of the terrestrial slug Limax located at the dorsal surface of the visceral ganglia. In the present study, we further analyzed the morphological features of these neurons by an intracellular injection of Lucifer yellow, and found that these neurons extend neurites out of the brain through at least 5 nerve bundles. We then isolated a gene and a cDNA clone potentially encoding a NdWFamide precursor, and investigated expression at the levels of mRNA and protein in Limax. The NdWFamide gene consists of 5 exons spanning at least 17 kb of the genome, and its open reading frame extends over 3 exons. The spatial expression pattern of NdWFamide mRNA was almost identical to that of the NdWFamide peptide, with some minor discrepancies in between. Although the most remarkable expression was evident in the visceral giant cells, we also found the expression of NdWFamide mRNA and peptide in the cerebral and pedal ganglia. These results suggest the involvement of NdWFamide in the regulation of a broad area of the slug's body.
三肽 Asn-d-Trp-Phe-NH(2)（NdWFamide）是一种含有 D-氨基酸的心脏兴奋肽，最初从海兔 Aplysia 中分离出来。先前我们在位于内脏神经节背面的陆地蜗牛 Limax 的内脏巨细胞中检测到 NdWFamide 免疫反应性。在本研究中，我们通过 Lucifer yellow 的细胞内注射进一步分析了这些神经元的形态特征，发现这些神经元通过至少 5 个神经束从脑中伸出神经突。然后，我们分离出一个基因和一个 cDNA 克隆，它们可能编码 NdWFamide 前体，并在 Limax 中研究了 mRNA 和蛋白质的表达水平。NdWFamide 基因由 5 个外显子组成，跨越基因组的至少 17 kb，其开放阅读框跨越 3 个外显子。NdWFamide mRNA 的空间表达模式与 NdWFamide 肽的表达模式几乎完全相同，只是略有差异。虽然在内脏巨细胞中表现最为明显，但我们也发现了 NdWFamide mRNA 和肽在脑和足神经节中的表达。这些结果表明 NdWFamide 参与了对蜗牛身体广泛区域的调节。
