Noxious tooth pulp stimulation suppresses c-fos expression in the rat hippocampal formation

Makoto Funahashi, Yi Fen He, Tomosada Sugimoto, Ryuji Matsuo

Research output: Contribution to journalArticle

19 Citations (Scopus)

Abstract

Changes in the expression of immediate early gene c-fos by noxious mechanical stimulation to the mandibular incisor pulp of rats were immunohistochemically examined in the hippocampus (Ammon's horn and dentate gyrus) and the retrohippocampus (subiculum, presubiculum, parasubiculum and entorhinal cortex). The highest control levels were found in subiculum, CA1, dentate and deep medial entorhinal cortex. Lower, but substantial levels were present in the other areas. Whereas weak dentinal stimulation caused increases in c-fos expression in some regions which were not statistically significant, strong tooth pulp stimulation caused a bilateral decrease in c- fos expression in every region except contralateral subiculum. These decreases reached statistical significance in superficial layer parasubiculum bilaterally (p < 0.01), bilateral CA1 and ipsilateral side of superficial layer of medial entorhinal cortex (p < 0.05). We suggest that inhibitory circuitry in hippocampal formation regions may be activated by peripheral noxious somatosensory inputs and this change in activity is accompanied by a change in the expression of the immediate early gene, c-fos.

Original languageEnglish
Pages (from-to)215-220
Number of pages6
JournalBrain Research
Volume827
Issue number1-2
DOIs
Publication statusPublished - May 8 1999

Keywords

  • C-fos
  • Hippocampal formation
  • Nociception
  • Rat

ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Clinical Neurology
  • Developmental Biology

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