Injury-induced expression of endothelial nitric oxide synthase by glial and microglial cells in the leech central nervous system within minutes after injury

O. T. Shafer, A. Chen, S. M. Kumar, K. J. Muller, C. L. Sahley

Research output: Contribution to journalArticle

35 Scopus citations

Abstract

It is known that nitric oxide (NO) is produced by injured tissues of the mammalian central nervous system (CNS) within days of injury. The aim of the present experiments was to determine the cellular synthesis of NO in the CNS immediately after injury, using the CNS of the leech which is capable of synapse regeneration, as a step towards understanding the role of NO in nerve repair. We report that within minutes after crushing the nerve cord of the leech, the region of damage stained histochemically for NADPH diaphorase, which is indicative of nitric oxide synthase (NOS) activity and was immunoreactive for endothelial NOS (eNOS). On immunoblots of leech CNS extract, the same antibody detected a band with a relative molecular mass of 140,000, which is approximately the size of vertebrate eNOS. Cells expressing eNOS immunoreactivity as a result of injury were identified after freezing nerve cords, a procedure that produced less tissue distortion than mechanical crushing. Immunoreactive cells included connective glia and some microglia. Calmodulin was necessary for the eNOS immunoreactivity: it was blocked by calmodulin antagonist W7 (25 μM), but not by similar concentrations of the less potent calmodulin antagonist W12. Thus in the leech CNS, in which axon and synapse regeneration is successful, an increase in NOS activity at lesions appears to be among the earliest responses to injury and may be important for repair of axons.

Original languageEnglish (US)
Pages (from-to)2171-2175
Number of pages5
JournalProceedings of the Royal Society B: Biological Sciences
Volume265
Issue number1411
DOIs
StatePublished - Nov 22 1998

Keywords

  • Calmodulin antagonists
  • Endothelial nitric oxide synthase
  • Hirudo medicinalis
  • Nerve injury
  • Nitric oxide
  • Nitric oxide synthase

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Agricultural and Biological Sciences (miscellaneous)

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