Calcium-induced long-term potentiation in the hippocampal slice: Characterization of the time course and conditions

K. G. Reymann, H. K. Matthies, U. Frey, V. S. Vorobyev, H. Matthies

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

A transient increase in extracellular calcium concentration causes a long-lasting enhancement of radiatum fibers evoked excitatory postsynaptic potential and population spike responses of CA1 pyramidal neurons which resembles long-term potentiation (LTP). The duration of this potentiation is much longer than described previously and is probably limited by the survival of the preparation itself (>8 hr). Therefore, Ca-induced LTP can be used for the investigation of a postulated late phase of LTP. Ca effects were activity-independent, since the subsequently evoked responses were facilitated even when the presynaptic fibers were not concurrently stimulated during or immediately after superfusion with the high Ca medium. In contrast, if too frequent testing of the synaptic input was done during the high Ca pulse, a short lasting depression instead of potentiation was observed. A lower extracellular magnesium concentration in the standard medium (1.3 instead of 2.0 mM MgSO4) prevents the potentiation of the EPSP at least for the first few hours. Presumably, both tetanus- and Ca-induced LTP share some common mechanisms, since an additional tetanization after Ca induction was not followed by an additional LTP. Compared to the potentiation following tetanization, the Ca-induced LTP was, however, not accompanied by a potentiation of the EPSP/spike ratio within the range of the population spike threshold intensity.

Original languageEnglish (US)
Pages (from-to)291-296
Number of pages6
JournalBrain Research Bulletin
Volume17
Issue number3
DOIs
StatePublished - Sep 1986
Externally publishedYes

Keywords

  • CA1
  • Calcium
  • Field potential
  • Hippocampus
  • Long-term potentiation
  • Rat
  • Synaptic transmission

ASJC Scopus subject areas

  • General Neuroscience

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