Activity-dependent short-term enhancement of intercellular coupling

Alberto E. Pereda, Donald S. Faber

Research output: Contribution to journalArticle

99 Scopus citations

Abstract

It was reported previously that repeated brief tetanization of the posterior eighth nerve can produce long-term homosynaptic potentiations of the electrotonic and chemical components of the mixed EPSP evoked in the Mauthner cell lateral dendrite by a single stimulus to the nerve. We show here that the same stimulus paradigm can lead, alternatively, to short-term enhancements of both excitatory responses. These transient modifications last for ~3 min, with a time course similar to post-tetanic potentiation at chemical synapses. However, a different stimulus pattern that transiently increases the presynaptic calcium concentration, paired-nerve stimuli, does not have any significant effect on electrotonic transmission, whereas it facilitates the chemically mediated EPSP. On the other hand, induction of the short-lasting potentiation of coupling, which depended on the discontinuous or burst-like property of the tetanizing paradigm, required NMDA-receptor activation and was blocked by postsynaptic intradendritic injections of the calcium chelator bis(2-aminophenoxy)ethane-N,N,N',N'-tetra-acetic acid. The ineffectiveness of presynaptic calcium in potentiating electrotonic coupling likely reflects the involvement of a calcium-dependent regulatory protein in the postsynaptic cell and suggests that hemichannels on the two aides of a gap junction plaque can be modified independently. NMDA-mediated modulation of gap junctions could be widespread, because both types of channels coexist during development and in several mammalian adult central nervous system structures such as hippocampus.

Original languageEnglish (US)
Pages (from-to)983-992
Number of pages10
JournalJournal of Neuroscience
Volume16
Issue number3
DOIs
StatePublished - Feb 1 1996

Keywords

  • Mauthner cell
  • NMDA
  • activity-dependent plasticity
  • calcium
  • electrical synapses
  • gap junctions
  • glutamate

ASJC Scopus subject areas

  • Neuroscience(all)

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