Limits to the development of fast neuromuscular transmission in zebrafish

Pierre Drapeau, Robert R. Buss, Declan W. Ali, Pascal Legendre, Richard L Rotundo

Research output: Contribution to journalArticle

15 Citations (Scopus)

Abstract

Zebrafish embryos have small and slow miniature end-plate currents (mEPCs), whereas only a few days later larval mEPCs are an order of magnitude larger and faster, being among the fastest of all neuromuscular synapses. To identify the bases for these changes we compared, in embryos and larvae, the properties and distributions of acetylcholine (ACh) receptors (AChRs) and acetylcholinesterase (AChE) as well as the ultrastructure of the developing neuromuscular junctions (NMJs). To mimic synaptic release, patches of muscle membrane were exposed briefly (for 1 ms) to a saturating concentration (10 mM) of ACh. The AChR deactivation kinetics were twice as slow in embryos compared with larvae. In both embryos and larvae, AChRs demonstrated open channel block by millimolar ACh, and this was detected during mEPCs, indicating that a high concentration of ACh is released at immature and mature NMJs. AChR and AChE distributions were compared using the selective fluorescently conjugated labels α-bungarotoxin and fasciculin 2, respectively. In larvae, punctate AChR clusters were detected whereas junctional AChE staining was less intense than that found at adult NMJs. Transmission electron microscopy revealed immature nerve endings in embryos that were closely juxtaposed to the surrounding muscle cells, whereas mature larval NMJs had a wider synaptic cleft with a conspicuous basal lamina over a limited region of synaptic contact. Our results indicate that ACh is released at high concentrations at immature NMJs, but its clearance is prolonged and the AChRs are dispersed, resulting in a slow mEPC time course until a mature cleft appears with densely packed faster AChRs and abundant AChE.

Original languageEnglish
Pages (from-to)2951-2956
Number of pages6
JournalJournal of Neurophysiology
Volume86
Issue number6
StatePublished - Dec 27 2001

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Cholinergic Receptors
Zebrafish
Neuromuscular Junction
Acetylcholinesterase
Embryonic Structures
Acetylcholine
Larva
Bungarotoxins
Nerve Endings
Transmission Electron Microscopy
Basement Membrane
Synapses
Muscle Cells
Staining and Labeling
Muscles
Membranes

ASJC Scopus subject areas

  • Physiology
  • Neuroscience(all)

Cite this

Drapeau, P., Buss, R. R., Ali, D. W., Legendre, P., & Rotundo, R. L. (2001). Limits to the development of fast neuromuscular transmission in zebrafish. Journal of Neurophysiology, 86(6), 2951-2956.

Limits to the development of fast neuromuscular transmission in zebrafish. / Drapeau, Pierre; Buss, Robert R.; Ali, Declan W.; Legendre, Pascal; Rotundo, Richard L.

In: Journal of Neurophysiology, Vol. 86, No. 6, 27.12.2001, p. 2951-2956.

Research output: Contribution to journalArticle

Drapeau, P, Buss, RR, Ali, DW, Legendre, P & Rotundo, RL 2001, 'Limits to the development of fast neuromuscular transmission in zebrafish', Journal of Neurophysiology, vol. 86, no. 6, pp. 2951-2956.
Drapeau, Pierre ; Buss, Robert R. ; Ali, Declan W. ; Legendre, Pascal ; Rotundo, Richard L. / Limits to the development of fast neuromuscular transmission in zebrafish. In: Journal of Neurophysiology. 2001 ; Vol. 86, No. 6. pp. 2951-2956.
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