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Acta Neuropathologica

, Volume 99, Issue 2, pp 109–116 | Cite as

Time course of ultrastructural changes and immunoelectron microscopic localization of neurocalcin in motor endplates of the lumbrical muscles of rats given a single administration of 2,5-di(tert-butyl)-1,4-hydroquinone

  • Takayoshi Imazawa
  • Kunitoshi Mitsumori
  • Satoshi Kitajima
  • Hiroshi Onodera
  • Toru Tamura
  • Michihito Takahashi
  • Masao Hirose
Regular paper

Abstract

A time-course study of ultrastructural changes and immunoelectron microscopic localization of neurocalcin was performed on motor endplates of the lumbrical muscles of female Wistar rats given a single oral administration of 2,5-di(tert-butyl)-1,4-hydroquinone (DTBHQ) at a dose of 120 mg/kg. Toxic signs such as salivation and muscle weakness of the hind legs appeared from 3 h after DTBHQ administration. No remarkable macroscopic or light microscopic changes were noted in the lumbrical muscles of the treated rats. At the ultrastructural level, neurotoxicity characterized by a decreases or loss of synaptic vesicles and mitochondria was observed after 24 h and at the 1-week time point, nerve endings had disappeared in some of the motor endplates, while many neurite nerve endings suggestive of early stage regeneration were apparent. After 6 weeks, newly formed reinnervated endplates were observed. Immunoelectron microscopically, the synaptic vesicle membranes were heavily labeled for neurocalcin in the control rats, but not at 24 h after DTBHQ treatment. Synaptic vesicle membranes in the DTBHQ group were weakly labeled at 1 week, but strongly at 6 weeks. The results strongly suggest that DTBHQ targets the motor endplates in the rat lumbrical muscles, causing depletion of neurocalcin in the synaptic vesicles followed by their loss.

Key words 2,5-Di(tert-butyl)-1,4-hydroquinone (DTBHQ) Wistar rat Motor endplate Lumbrical ¶muscle Neurocalcin 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2000

Authors and Affiliations

  • Takayoshi Imazawa
    • 1
  • Kunitoshi Mitsumori
    • 1
  • Satoshi Kitajima
    • 2
  • Hiroshi Onodera
    • 1
  • Toru Tamura
    • 1
  • Michihito Takahashi
    • 1
  • Masao Hirose
    • 1
  1. 1.Division of Pathology, Biological Safety Research Center, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158–8501, Japan Tel.: +81-3-37009845, Fax: +81-3-37001425JP
  2. 2.Division of Toxicology, National Institute of Health Sciences, Setagaya-ku, Tokyo 158–8501, JapanJP

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