Identification and distribution of tryptophan hydroxylase (TPH)-positive neurons in the planarian Dugesia japonica

Neurosci Res. 2007 Sep;59(1):101-6. doi: 10.1016/j.neures.2007.05.014. Epub 2007 Jun 3.


We identified a full-length tryptophan hydroxylase (TPH) gene of planarian Dugesia japonica from a head EST database, and named it DjTPH. Based on whole-mount in situ hybridization and immunofluorescence analyses, DjTPH mRNA and protein were mainly expressed in the nervous system, especially ventral nerve cords and eye pigment cells. Furthermore, DjTPH immunoreactivity was clearly detected at commissure axonal connections in the ventral nerve cords. 5-HT was significantly decreased in DjTPH-knockdown planarians compared with control animals. These results suggest that DjTPH is required for 5-HT biosynthesis, and DjTPH antibody is a useful marker for serotonergic neurons in planarians.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Arrestin / metabolism
  • Central Nervous System / cytology
  • Central Nervous System / enzymology
  • Eye / cytology
  • Eye / enzymology
  • In Situ Hybridization
  • Neurons / drug effects
  • Neurons / enzymology*
  • Planarians / cytology*
  • Planarians / enzymology*
  • RNA, Double-Stranded / pharmacology
  • Serotonin / pharmacology
  • Tryptophan Hydroxylase / metabolism*


  • Arrestin
  • RNA, Double-Stranded
  • Serotonin
  • Tryptophan Hydroxylase