Differential physiology and morphology of motor axons to ventral longitudinal muscles in larval Drosophila

P Kurdyak; H L Atwood; B A Stewart; C F Wu

doi:10.1002/cne.903500310

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Differential physiology and morphology of motor axons to ventral longitudinal muscles in larval Drosophila

Journal article

Peer reviewed

Differential physiology and morphology of motor axons to ventral longitudinal muscles in larval Drosophila

P Kurdyak, H L Atwood, B A Stewart and C F Wu

Journal of comparative neurology (1911), Vol.350(3), pp.463-472

12/15/1994

DOI: 10.1002/cne.903500310

PMID: 7884051

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Abstract

Morphological and physiological characteristics of the two major motor axons supplying the commonly studied ventral longitudinal muscle fibers (6 and 7) of third-instar Drosophila melanogaster larvae were investigated. The innervating terminals of the two motor axons differ in the size of their synapse-bearing varicosities. The terminal with the larger varicosities also fluoresces more brightly when stained with the vital fluorescent dye 4-(4-diethylaminostyryl)-N-methylpyridinium iodide (4-Di-2-Asp) and occupies a larger total contact area on the muscle fiber. Through selective simultaneous recording of synaptic currents from identified boutons in living preparations during elicitation of synaptic potentials, it was shown that the axon with the smaller varicosities generates a large excitatory junction potential (EJP) in muscle 6 and that the axon with the larger varicosities generates a smaller EJP. Short-term facilitation is more pronounced for the smaller EJP. In preparations treated with 4-Di-2-Asp, the fluorescence of smaller varicosities increases with stimulation that elicits the large EJPs, indicating an activity-dependent entry of calcium that enhances mitochondrial fluorescence. The differences in morphology and physiology of the two axons are similar to, though less pronounced than, those observed in "phasic" and "tonic" motor axons of crustaceans.

Motor Neurons - physiology

Neuromuscular Junction - cytology

Drosophila melanogaster - physiology

Pyridinium Compounds

Axons - physiology

Membrane Potentials - physiology

Animals

Larva

Muscle Fibers, Skeletal

Motor Neurons - cytology

Axons - ultrastructure

Muscles - innervation

Fluorescent Dyes

Microscopy, Fluorescence

Neuromuscular Junction - physiology

Details

Title: Subtitle: Differential physiology and morphology of motor axons to ventral longitudinal muscles in larval Drosophila
Creators: P Kurdyak - Department of Physiology, University of Toronto, Ontario, Canada
H L Atwood
B A Stewart
C F Wu
Resource Type: Journal article
Publication Details: Journal of comparative neurology (1911), Vol.350(3), pp.463-472
Publisher: United States
DOI: 10.1002/cne.903500310
PMID: 7884051
ISSN: 0021-9967
eISSN: 1096-9861
Grant note: HP 18577 / PHS HHS NS 26528 / NINDS NIH HHS NS 15350 / NINDS NIH HHS
Language: English
Date published: 12/15/1994
Academic Unit: Iowa Neuroscience Institute; Biology
Record Identifier: 9984070775902771

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156 Times Cited - Web of Science