Long-term potentiation of hippocampal mossy fiber synapses is blocked by postsynaptic injection of calcium chelators

Neuron. 1989 Nov;3(5):583-8. doi: 10.1016/0896-6273(89)90268-7.


The role of intracellular calcium in an APV-insensitive form of long-term potentiation (LTP) has been studied at the hippocampal mossy fiber synapse. Intracellular calcium was buffered by iontophoretic injection of either BAPTA or QUIN-2, into CA3 pyramidal neurons. The slow calcium-dependent after hyperpolarization was used as an indicator of buffering. LTP was elicited in control and in APV-treated cells (6/6 and 4/5 cell, respectively). In contrast, LTP was observed in only 2/9 BAPTA-loaded cells and in 1/4 QUIN-2-loaded cells. The magnitude of LTP for control and APV-treated cells were not significantly different, but both groups showed significantly greater LTP than BAPTA-loaded cells. These results suggest that an increase in postsynaptic calcium is required for the induction of mossy fiber LTP.

Publication types

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

MeSH terms

  • 2-Amino-5-phosphonovalerate / pharmacology*
  • Aminoquinolines / pharmacology
  • Animals
  • Calcium*
  • Cell Survival / drug effects
  • Chelating Agents / pharmacology*
  • Egtazic Acid / pharmacology
  • Hippocampus / cytology
  • Hippocampus / physiology*
  • Injections
  • Nerve Fibers / physiology*
  • Rats
  • Synapses / physiology*
  • Time Factors


  • Aminoquinolines
  • Chelating Agents
  • Egtazic Acid
  • 2-Amino-5-phosphonovalerate
  • 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid
  • Quin2
  • Calcium