Excitation of cells in the rostral medial medulla of the rat by the nitric oxidecyclic guanosine monophosphate messenger system

Ian D. Hental

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5 Scopus citations


Analgesia has been reported to be facilitated by supraspinal nitric oxide (NO) and cyclic guanosine monophosphate (cGMP). In the rostromedial medulla, an important pain-suppressing region, iontophoretically delivered 8-bromo-cGMP excited most single recorded cells ( 9 10), and methylene blue (a guanylyl cyclase inhibitor) inhibited all cells ( 7 7). Nitrite and ferrous ions together, shown voltammetrically ex vivo to yield nitric oxide (NO), excited some cells ( 14 28) and inhibited others ( 7 28). Methylene blue blocked excitation ( 3 3) but not inhibition ( 4 4) by the putative NO. Spontaneous or glutamate-evoked firing was gradually inhibited ( 23 32) or unaffected by Nω-nitro-l-arginine (a NO synthase inhibitor), but was mostly inhibited by l-arginine (the NO precursor) ( 23 26), although a rapid onset militated against elevated NO production. These substances, excepting l-arginine, produced changes consistent with an excitatory cGMP-NO cascade contributing to analgesia.

Original languageEnglish (US)
Pages (from-to)155-158
Number of pages4
JournalNeuroscience Letters
Issue number3
StatePublished - Aug 11 1995



  • Guanylyl cyclase
  • Iron
  • l-Arginine
  • Methylene blue
  • Nitrite
  • Raphe

ASJC Scopus subject areas

  • Neuroscience(all)

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