Multiple forms of LTP in hippocampal CA3 neurons use a common postsynaptic mechanism

Nat Neurosci. 1999 Jul;2(7):625-33. doi: 10.1038/10180.


We investigated long-term potentiation (LTP) at mossy fiber synapses on CA3 pyramidal neurons in the hippocampus. Using Ca2+ imaging techniques, we show here that when postsynaptic Ca2+ was sufficiently buffered so that [Ca2+]i did not rise during synaptic stimulation, the induction of mossy fiber LTP was prevented. In addition, induction of mossy fiber LTP was suppressed by postsynaptic injection of a peptide inhibitor of cAMP-dependent protein kinase. Finally, when ionotropic glutamate receptors were blocked, LTP depended on the postsynaptic release of Ca2+ from internal stores triggered by activation of metabotropic glutamate receptors. These results support the conclusion that mossy fiber LTP and LTP at other hippocampal synapses share a common induction mechanism involving an initial rise in postsynaptic [Ca2+].

Publication types

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

MeSH terms

  • Animals
  • Axons / physiology
  • Calcium / metabolism
  • Chelating Agents / pharmacology
  • Egtazic Acid / analogs & derivatives
  • Egtazic Acid / pharmacology
  • Electric Stimulation
  • Excitatory Postsynaptic Potentials / physiology*
  • Hippocampus / physiology*
  • In Vitro Techniques
  • Long-Term Potentiation / drug effects
  • Long-Term Potentiation / physiology*
  • Nerve Fibers / physiology
  • Patch-Clamp Techniques
  • Pyramidal Cells / physiology*
  • Rats
  • Rats, Sprague-Dawley
  • Time Factors


  • Chelating Agents
  • Egtazic Acid
  • 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid
  • Calcium