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Experimental Brain Research

, Volume 114, Issue 2, pp 205–213 | Cite as

Reciprocal changes in expression of mRNA for nerve growth factor and its receptors TrkA and LNGFR in brain of aged rats in relation to maze learning deficits

  • R. U. Hasenöhrl
  • S. Söderström
  • A. H. Mohammed
  • T. Ebendal
  • J. P. Huston
RESEARCH ARTICLE

Abstract

 Quantitative in situ hybridization was used to examine the expression of mRNA for nerve growth factor (NGF) and its receptors, p140Trk (TrkA) and p75LNGFR (LNGFR), in different brain regions of adult (3-month-old) and aged (27-month-old) Wistar rats. The brain regions studied were hippocampus (dentate gyrus, CA3 region), basal forebrain (medial septum, diagonal band) and caudate-putamen. Prior to hybridization histochemistry behaviorally impaired as well as severely impaired animals were selected from a large group of old rats according to their performance in the Morris water maze. The impaired rats showed longer escape latencies and, thus, implicitly impaired performance in the place version of the task, but did not differ from adult controls on the platform crossing measure registered during the spatial probe trial. The severely impaired rats were significantly impaired on both measures, both in comparison with the adult animals and in comparison with the impaired aged rats. Inspection of the hippocampus revealed no age- or performance-related changes in NGF mRNA levels. The overall expression of TrkA mRNA in basal forebrain and caudate was found to be decreased in the impaired (–20%) as well as the severely impaired aged rats (–17%). A significant increase in p75LNGFR mRNA was found in the basal forebrain of the impaired rats in comparison with the severely impaired aged rats (+35%) and adult animals (+33%). These findings show that age-related maze performance deficits are accompanied by a decrease in basal forebrain and striatal TrkA mRNA expression. The increase in basal forebrain LNGFR mRNA levels observed in impaired, but not severely impaired, aged rats may reflect an early manifestation of processes underlying age-related cognitive deficits and may constitute a restorative and/or compensatory mechanism, since these rats displayed fewer deficits in navigation of the maze.

Key words Nerve growth factor Low-affinity NGF receptor Tyrosine receptor kinase Hippocampus Basal forebrain Caudate-putamen Learning Aging In situ hybridization 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • R. U. Hasenöhrl
    • 1
  • S. Söderström
    • 2
  • A. H. Mohammed
    • 3
  • T. Ebendal
    • 2
  • J. P. Huston
    • 1
  1. 1.Institut für Physiologische Psychologie and Biologisch-Medizinisches Forschungszentrum, Universität Düsseldorf, Universitätsstrasse 1, D-40225 Düsseldorf, Germany; Tel.: +49 (211) 81–14299, Fax: +49 (211) 81–12024, e-mail: hasenoeh@uni-duesseldorf.deDE
  2. 2.Department of Developmental Neuroscience, Uppsala University, Biomedical Center, Box 587, S-75123 Uppsala, SwedenSE
  3. 3.Department of Clinical Neuroscience and Family Medicine, Karolinska Institute, Huddinge University Hospital, S-14186 Huddinge, SwedenSE

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