Dopaminergic modulation of motor neuron activity and neuromuscular function in Drosophila melanogaster

R. L. Cooper, W. S. Neckameyer

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

Dopamine is found in both neuronal and non-neuronal tissues in the larval stage of the fruit fly, Drosophila melanogaster, and functions as a signaling molecule in the nervous system. Although dopaminergic neurons in the central nervous system (CNS) were previously thought solely to be interneurons, recent studies suggest that dopamine may also act as a neuromodulator in humoral pathways. We examined both application of dopamine on intact larval CNS-segmental preparations and isolated neuromuscular junctions (NMJs). Dopamine rapidly decreased the rhythmicity of the CNS motor activity. Application of dopamine on neuromuscular preparations of the segmental muscles 6 and 7 resulted in a dose-responsive decrease in the excitatory junction potentials (EJPs). With the use of focal, macro-patch synaptic current recordings the quantal evoked transmission showed a depression of vesicular release at concentrations of 10 μM. Higher concentrations (1 mM) produced a rapid decrement in evoked vesicular release. Dopamine did not alter the shape of the spontaneous synaptic currents, suggesting that dopamine does not alter the postsynaptic muscle fiber receptiveness to the glutaminergic motor nerve transmission. The effects are presynaptic in causing a reduction in the number of vesicles that are stimulated to be released due to neural activity. Copyright (C) 1999 Elsevier Science Inc.

Original languageEnglish
Pages (from-to)199-210
Number of pages12
JournalComparative Biochemistry and Physiology - B Biochemistry and Molecular Biology
Volume122
Issue number2
DOIs
StatePublished - 1999

Bibliographical note

Funding Information:
Illustrations were provided by the courtesy of Hye Won Cooper. We thank Joe Wegrzyn (University of Kentucky) for editorial assistance. Funding was provided by University of Kentucky Research and Graduate Studies Office (R.L.C.) and NSF grants IBN-9808631 (R. Cooper) and IBN-9423616 (W. Neckameyer).

Keywords

  • Dopamine
  • Drosophila
  • Neuromodulation
  • Synaptic

ASJC Scopus subject areas

  • Aquatic Science
  • Animal Science and Zoology
  • Molecular Biology
  • Biochemistry
  • Physiology

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