Neuropeptides and Their Receptors of the Protochordate, Ciona intestinalis: The Evolutionary Origin of Vertebrate Neuropeptides

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Ci-TK and Ci-TK-R are authentic tachykinin (TK) and TK receptor isolated from a protochordate, Ciona intestinalis. In this study, we investigated a novel function of TK as an enhancer of oocyte growth. Ci- TK-R is expressed specifically in the Ciona vitellogenic oocytes. Moreover, administration of Ci-TK to the Ciona ovary resulted in upregulation of gene expression and enzymatic activity of several proteases. Moreover, maturation of the Ciona oocytes from the vitellogenic stage to the post-vitellogenic stage was induced in the presence of Ci-TK, which was completely blocked by addition of protease inhibitors.


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Correspondence to H. Satake.

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Satake, H., Aoyama, M., Kawada, T. et al. Neuropeptides and Their Receptors of the Protochordate, Ciona intestinalis: The Evolutionary Origin of Vertebrate Neuropeptides. BIOLOGIA FUTURA 59, 237–239 (2008).

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  • Tachykinin
  • ascidian
  • Ciona intestinalis
  • neuropeptide
  • oocyte