Experimental Brain Research

, Volume 114, Issue 2, pp 279–287 | Cite as

Failure in learning task and loss of cortical cholinergic fibers in microsphere-embolized rats

  • Norio Takagi
  • Keiko Miyake
  • T. Taguchi
  • Hiroaki Tamada
  • Kaori Takagi
  • Naoko Sugita
  • S. Takeo
RESEARCH ARTICLE

Abstract

 The present study was undertaken to elucidate the pathological changes in learning and memory functions and in the metabolism of cortical cholinergic neurons following microsphere embolism in the rat. Microspheres (48 μm) were injected into the right internal carotid artery of rats. Learning and memory functions were measured 7 or more days after the embolism by active and passive avoidance, and water maze tasks. In the biochemical study, cortical acetylcholine and choline contents, and choline acetyltransferase activity were measured. Cortical acetylcholinesterase-containing fibers were quantitatively estimated in the embolized rat. The active and passive avoidance, and water maze tasks were impaired in the microsphere-embolized rat. In the histochemical study, the density of cortical acetylcholinesterase-containing fibers of the ipsilateral hemisphere of the microsphere-embolized rat was decreased, but cell density was unchanged. Furthermore, microsphere embolism decreased the cortical acetylcholine concentration and choline acetyltransferase activity and increased the choline concentration. The results suggest that microsphere embolism causes severe damage to cortical cholinergic neurons, which may be, at least in part, related to the impairment of learning and memory functions in the sustained brain ischemia.

Key words Acetylcholine Acetylcholinesterase-containing fibers Learning task Microsphere embolism Rats 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Norio Takagi
    • 1
  • Keiko Miyake
    • 1
  • T. Taguchi
    • 1
  • Hiroaki Tamada
    • 1
  • Kaori Takagi
    • 1
  • Naoko Sugita
    • 1
  • S. Takeo
    • 1
  1. 1.Department of Pharmacology, Tokyo University of Pharmacy and Life Science, 1432–1, Horinouchi, Hachioji, Tokyo 192–03, Japan; Tel.: +81–426–76–4583, Fax: +81–426–76–5560JP

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