Neurogranin null mutant mice display performance deficits on spatial learning tasks with anxiety related components

Authors

  • Tsuyoshi Miyakawa,

    1. Section on Behavioral Neuropharmacology, Experimental Therapeutics Branch, National Institute of Mental Health, Bethesda, Maryland
    Search for more papers by this author
  • Edom Yared,

    1. Section on Behavioral Neuropharmacology, Experimental Therapeutics Branch, National Institute of Mental Health, Bethesda, Maryland
    Search for more papers by this author
  • Jhang Ho Pak,

    1. Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
    Search for more papers by this author
  • Freesia L. Huang,

    1. Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
    Search for more papers by this author
  • Kuo-Ping Huang,

    1. Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
    Search for more papers by this author
  • Jacqueline N. Crawley

    Corresponding author
    1. Section on Behavioral Neuropharmacology, Experimental Therapeutics Branch, National Institute of Mental Health, Bethesda, Maryland
    • Section on Behavioral Neuropharmacology, Experimental Therapeutics Branch, National Institute of Mental Health, Building 10, Room 4D11, Bethesda, MD 20892-1375
    Search for more papers by this author

  • This article is a US Government work and, as such, is in the public domain in the United States of America.

Abstract

Neurogranin/RC3 is a protein that binds calmodulin and serves as a substrate for protein kinase C. Neuronally distributed in the hippocampus and forebrain, neurogranin is highly expressed in dendritic spines of hippocampal pyramidal cells, implicating this protein in long-term potentiation and in learning and memory processes. Null mutation of the neurogranin gene Ng generated viable knockout mice for analysis of the behavioral phenotype resulting from the absence of neurogranin protein. Ng −/− mice were normal on measures of general health, neurological reflexes, sensory abilities, and motor functions, as compared to wild type littermate controls. On the Morris water task, Ng −/− mice failed to reach acquisition criterion on the hidden platform test and did not show selective search on the probe trial. In the Barnes circular maze, another test for spatial navigation learning, Ng −/− mice showed impairments on some components of transfer, but normal performance on time spent around the target hole. Abnormal and idiosyncratic behaviors were detected, that appeared to represent an anxiogenic phenotype in Ng −/− mice, as measured in the light↔dark exploration test and the open field center time parameter. These findings of apparent deficits in spatial learning and anxiety-like tendencies in Ng −/− support a role for neurogranin in the hippocampally-mediated interaction between stress and performance. Hippocampus 2001;11:763–775. Published 2001 Wiley-Liss, Inc.

Ancillary