Visualization of nitric oxide production in the earthworm ventral nerve cord

Yoshiichiro Kitamura, Yuichi Naganoma, Haruhito Horita, Noriko Tsuji, Ryosaku Shimizu, Hiroto Ogawa, Kotaro Oka

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Distribution of nitric oxide (NO)-producible neurons in the ventral nerve cord (VNC) of the earthworm was investigated by nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry. Some neurons (20-30 μm in diameter) were intensely stained and were localized in areas between the 1st and 2nd lateral nerves in the ventral side of VNC. In contrast, no neurons including giant fibers were stained in the dorsal side. Endogenous NO production from VNC was visualized using a fluorescent dye, diaminofluorescein-2 diacethyl (DAF-2 DA). When VNC was incubated in a saline, a relative high level of NO was produced from the ventral side, especially from NADPH-d-positive neurons. Under high-K+ stimulation, NO was also detected in the giant fibers in the dorsal side of VNC. Our results suggest that the earthworm VNC constantly and relative highly produces NO as a neuromodulator, and that NO produced from the ventral side sometimes reaches and affects the giant fibers. In conclusion, we successfully visualized NO in the earthworm VNC by clarifying both the distribution of NO-producible neurons and the endogenous NO production.

Original languageEnglish
Pages (from-to)175-181
Number of pages7
JournalNeuroscience Research
Issue number2
Publication statusPublished - 2001


  • Diaminofluorescein-2 diacethyl (DAF-2 DA)
  • Earthworm
  • Histochemistry
  • Imaging
  • Nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d)
  • Nitric oxide (NO)
  • Serotonin
  • Ventral nerve cord (VNC)

ASJC Scopus subject areas

  • General Neuroscience


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