Different sensitivities to chemical and mechanical stimulations in heat-sensitive and -insensitive C-fiber sensory receptors recorded from rat muscle-nerve preparation in vitro

• Taguchi Toru

  Dept. Neural Regulation., Res. Inst. Environ. Med., Nagoya Univ, Nagoya, Japan

• Sato Jun

  Dept. Neural Regulation., Res. Inst. Environ. Med., Nagoya Univ, Nagoya, Japan

• Mizumura Kazue

  Dept. Neural Regulation., Res. Inst. Environ. Med., Nagoya Univ, Nagoya, Japan

Bibliographic Information

Other Title

• ラット神経–筋標本から記録したC線維受容器の化学および機械刺激に対する感受性は熱反応の有無により異なる

Abstract

The aim of this study was to characterize muscle C-fiber sensory receptors recorded in vitro. Activities of single nerve fibers (sensitive to pressure but not to stretch, conduction velocity<2.0 m/s) were recorded from extensor digitorum longus muscle-common peroneal nerve preparations in vitro. Twenty-seven fibers were recorded in total. The mechanical threshold distributed continuously, and no segregation was observed. Therefore, it was difficult to group fibers into low threshold or high threshold ones by mechanical threshold. However, there were clear differences in sensitivities between heat-sensitive and -insensitive fibers. Eleven out of 27 fibers were heat-sensitive. Conduction velocity of the heat-sensitive fibers was significantly slower than that of the heat-insensitive ones (0.43±0.04 (n=11) vs. 0.84±0.09 m/s (n=16), p<0.01). Although there was no difference in the mechanical threshold, the magnitude of the mechanical response was significantly smaller in heat-sensitive fibers. The percentage of fibers sensitive to ATP (10 mM) or bradykinin (BK, 10 µM) in the heat-sensitive fibers (80% or 100%) was significantly higher than that in the heat-insensitive ones (12.5% or 37.5%, p<0.05), and the response magnitude tended to be higher in heat-sensitive fibers than in heat-insensitive ones, though a significant difference was observed only in the BK response. These results suggest that heat-sensitive muscle C-fiber sensory receptors make a subgroup in C-fiber receptors. [Jpn J Physiol 55 Suppl:S228 (2005)]

Journal

• Proceedings of Annual Meeting of the Physiological Society of Japan

  Proceedings of Annual Meeting of the Physiological Society of Japan 2005 (0), S228-S228, 2005

  PHYSIOLOGICAL SOCIETY OF JAPAN

Keywords

• muscle
• C-fiber
• nociceptor
• heat
• rat

Details

• CRID: 1390282680704379136
• NII Article ID: 130005447800
• DOI: 10.14849/psjproc.2005.0_s228_2
• Data Source:
  • JaLC
  • CiNii Articles
• Abstract License Flag: Disallowed