Developmental changes in presynaptic calcium channels coupled to glutamate release in cultured rat hippocampal neurons

Kenneth P. Scholz*, Richard J. Miller

*Corresponding author for this work

Research output: Contribution to journalArticle

98 Scopus citations

Abstract

Excitatory synaptic transmission in the hippocampus involves the participation of at least two types of presynaptic Ca2+ channels, N-type channels sensitive to ω-conotoxin GVIA (ω-CTx GVIA) and Q-type channels sensitive to ω-agatoxin IVA (ω-Aga IVA). Hippocampal pyramidal neurons in cell culture were used to examine the participation of these two classes of channels at different stages of synapse development. Specific Ca2+ channel toxins were used to block presynaptic Ca2+ channels while whole-cell voltage-clamp recordings were used to record evoked EPSCs in postsynaptic neurons. At immature synapses (cells in culture for 10-15 d), ω-CTx GVIA (1- 5 μM) blocked transmission by more than 80% while ω-Aga IVA (1 μM) was less effective. In older cultures, however, ω-Aga IVA (1 μM) was more effective than ω-CTx GVIA (1-5 μM) in blocking synaptic transmission. The pharmacological properties of the ω-Aga IVA sensitive component of synaptic transmission were examined in more detail using ω-Aga IVA and ω-conotoxin MVIIC (ω-CTx MVIIC). The properties of this component of transmitter release indicated that a Q-type Ca2+ channel was involved in presynaptic Ca2+ entry. The results suggest that different classes of presynaptic Ca2+ channels begin to participate in transmitter release at different times during synapse development and maturation.

Original languageEnglish (US)
Pages (from-to)4612-4617
Number of pages6
JournalJournal of Neuroscience
Volume15
Issue number6
DOIs
StatePublished - Jun 1995

Keywords

  • EPSC
  • glutamate
  • presynaptic calcium channel
  • ω-agatoxin IVA
  • ω-conotoxin GVIA
  • ω-conotoxin MVIIC

ASJC Scopus subject areas

  • Neuroscience(all)

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