Intrathecal oxotremorine affects formalin-induced behavior and spinal nitric oxide synthase immunoreactivity in rats

B. Przewlocka, J. Mika, F. Capone, H. Machelska, F. Pavone

Research output: Contribution to journalArticle

Abstract

The present research was undertaken to investigate, by behavioral and immunohistochemical methods, the effects of intrathecal (ITH) injection of the muscarinic agonist oxotremorine on the response to the long-lasting nociceptive stimulus induced by injection of formalin into the rat hind paw. Formalin injection induced a biphasic, pain-induced behavioral response (paw jerks), as well as an increase in the number of nitric oxide (NO) synthase-labeled neurons in laminae I-III, IV, and X, but not in laminae V-VI. Oxotremorine (0.1-10 ng, ITH) inhibited paw-jerk frequency in both phases of formalin-induced behavior. The immunohistochemical results showed that ITH-injected oxotremorine differently affected the level of NO synthase in lumbar part of the spinal cord: no change or increase after the dose of 1 ng, and a significant reduction of nitric oxide synthase neurons after the higher dose (10 ng). These results evidenced a role of cholinergic system in the modulation of tonic pain and in nitric oxide synthase expression at the spinal cord level, which further suggests that these two systems could be involved in phenomena induced by long-lasting nociceptive stimulation. Copyright (C) 1999 Elsevier Science Inc.

Original languageEnglish
Pages (from-to)531-536
Number of pages6
JournalPharmacology, Biochemistry and Behavior
Volume62
Issue number3
DOIs
Publication statusPublished - Mar 1999

Keywords

  • Cholinergic antinociception
  • Formalin pain
  • Nitric oxide synthase
  • Oxotremorine
  • Rats
  • Spinal nociception

ASJC Scopus subject areas

  • Biochemistry
  • Behavioral Neuroscience
  • Pharmacology

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