Depression of synaptic efficacy in high- and low-output Drosophila neuromuscular junctions by the molting hormone (20-HE)

Marvin E. Ruffner, Stuart I. Cromarty, Robin L. Cooper

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

The molt-related steroid hormone, 20-hydroxyecdysone (20-HE), was applied to muscles 6 and 7 of third instar larval of Drosophila melanogaster neuromuscular junction preparations to examine if rapid, nongenomic responses could be observed as was shown recently to occur in crustacean neuromuscular junctions. At a dose of 10 μM, the excitatory junction potentials were reduced in amplitude within minutes. To elucidate the site of action of the hormone, focal-macropatch recordings of synaptic currents were obtained over the neuromuscular junctions. The results showed that the high-output (Is) and the low-output (Ib) motor nerve terminals, which innervate muscles 6 and 7, released fewer synaptic vesicles for each stimulation while exposed to 20- HE. Because the size and shape of synaptic currents from spontaneous releases did not change, the effects of the 20-HE are presynaptic. The rapid effects of this hormone may account in part for the quiescent behavior associated with molts among insects and crustaceans.

Original languageEnglish
Pages (from-to)788-794
Number of pages7
JournalJournal of Neurophysiology
Volume81
Issue number2
DOIs
StatePublished - 1999

ASJC Scopus subject areas

  • General Neuroscience
  • Physiology

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