Calcium channel isoforms underlying synaptic transmission at embryonic Xenopus neuromuscular junctions

C. Thaler, W. Li, Paul Brehm

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Studies on the amphibian neuromuscular junction have indicated that N-type calcium channels are the sole mediators of stimulus-evoked neurotransmitter release. We show, via both presynaptic and postsynaptic voltage-clamp measurements, that dihydropyridine (DHP)-sensitive calcium channels also contribute to stimulus-evoked release at developing Xenopus neuromuscular junctions. Whereas inhibition of postsynaptic responses by ω-conotoxin (ω-Ctx) GVIA has been taken previously as evidence that only N-type channels mediate transmitter release, we find that both N-type and DHP-sensitive calcium currents are sensitive to this toxin. The unusual sensitivity of DHP-sensitive calcium channels to ω-Ctx GVIA in presynaptic terminals raises the possibility that this channel type may have escaped detection in previous physiological studies on adult frog neuromuscular junctions. Alternatively, the additional channel isoforms may be present only during early development, when they may serve to strengthen collectively presynaptic release during critical periods of synaptogenesis.

Original languageEnglish (US)
Pages (from-to)412-422
Number of pages11
JournalJournal of Neuroscience
Volume21
Issue number2
StatePublished - Jan 15 2001
Externally publishedYes

Fingerprint

Neuromuscular Junction
Calcium Channels
Xenopus
Synaptic Transmission
Protein Isoforms
N-Type Calcium Channels
Conotoxins
Presynaptic Terminals
Amphibians
Anura
Neurotransmitter Agents
Calcium
1,4-dihydropyridine

Keywords

  • Acetylcholine receptor
  • Conotoxin
  • Dihydropyridine
  • End plate current
  • Exocytosis
  • Spinal neuron

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Calcium channel isoforms underlying synaptic transmission at embryonic Xenopus neuromuscular junctions. / Thaler, C.; Li, W.; Brehm, Paul.

In: Journal of Neuroscience, Vol. 21, No. 2, 15.01.2001, p. 412-422.

Research output: Contribution to journalArticle

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