Synaptic plasticity: LTP and LTD

Curr Opin Neurobiol. 1994 Jun;4(3):389-99. doi: 10.1016/0959-4388(94)90101-5.


Long-term potentiation (LTP) is a synaptic enhancement that follows brief, high-frequency electrical stimulation in the hippocampus and neocortex. Recent evidence suggests that induction of LTP may require, in addition to postsynaptic Ca2+ entry, activation of metabotropic glutamate receptors and the generation of diffusible intercellular messengers. A new form of synaptic plasticity, homosynaptic long-term depression (LTD) has also recently been documented, which, like LTP, requires Ca2+ entry through the NMDA receptor. Current work suggests that this LTD is a reversal of LTP, and vice versa, and that the mechanisms of LTP and LTD may converge at the level of specific phosphoproteins.

Publication types

  • Review

MeSH terms

  • Animals
  • Humans
  • Long-Term Potentiation*
  • Neuronal Plasticity*
  • Receptors, Metabotropic Glutamate / physiology
  • Second Messenger Systems
  • Synapses / physiology*


  • Receptors, Metabotropic Glutamate