A genetic test of the effects of mutations in PKA on mossy fiber LTP and its relation to spatial and contextual learning

Cell. 1995 Dec 29;83(7):1211-22. doi: 10.1016/0092-8674(95)90146-9.


Using a genetic approach, we assessed the effects of mutations in protein kinase A (PKA) on long-term potentiation (LTP) in the mossy fiber pathway and its relationship to spatial and contextual learning. Ablation by gene targeting of the C beta 1 or the RI beta isoform of PKA produces a selective defect in mossy fiber LTP, providing genetic evidence for the role of these isoforms in the mossy fiber pathway. Despite the elimination of mossy fiber LTP, the behavioral responses to novelty, spatial learning, and conditioning to context are unaffected. Thus, contrary to current theories about hippocampal function, mossy fiber LTP does not appear to be required for spatial or contextual learning. In the absence of mossy fiber LTP, adequate spatial and contextual information might reach the CA1 region via other pathways from the entorhinal cortex.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Colforsin / pharmacology
  • Conditioning, Psychological / physiology
  • Cyclic AMP-Dependent Protein Kinase RIbeta Subunit
  • Cyclic AMP-Dependent Protein Kinases / genetics*
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Electrophysiology
  • Female
  • Hippocampus / cytology*
  • Hippocampus / physiology
  • Isoenzymes
  • Isoproterenol / pharmacology
  • Long-Term Potentiation / genetics*
  • Male
  • Maze Learning / physiology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mutation
  • Spatial Behavior / physiology*


  • Cyclic AMP-Dependent Protein Kinase RIbeta Subunit
  • Isoenzymes
  • Prkar1b protein, mouse
  • Colforsin
  • Cyclic AMP-Dependent Protein Kinases
  • Isoproterenol