Morphological plasticity of motor axons in Drosophila mutants with altered excitability

Budnik, V., Zhong, Y., Wu, C. F. (November 1990) Morphological plasticity of motor axons in Drosophila mutants with altered excitability. J Neurosci, 10 (11). pp. 3754-68. ISSN 0270-6474 (Print)

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An anatomical and electrophysiological study of Drosophila mutants has been made to determine the effect of altered electrical activity on the development and maintenance of larval neuromuscular junctions. We examined motor axon terminals of (1) hyperexcitable mutants Shaker (Sh), ether a go-go (eag), Hyperkinetic (Hk), and Duplication of para+ (Dp para+); and (2) mutants with reduced excitability, no action potential (napts) and paralytic (parats 1). Nerve terminals innervating larval body-wall muscles were visualized by using anti-HRP immunocytochemistry, which specifically stains neurons in insect species. In wild-type larvae, motor axon terminals were distributed in a stereotypic fashion. However, in combinations of eag and Sh alleles, the basic pattern of innervation was altered. There was an increase in both the number of higher-order axonal branches over the muscles and the number of varicosities on the neurites. A similar phenomenon was found in the double mutant Hk eag and, to a lesser extent, in Dp para+ and Dp para+ Sh mutants. It is known that at permissive temperature the napts, but not parats 1, mutation decreases excitability of larval motor axons and suppresses the behavioral phenotypes of Sh, eag, and Hk. In the mutant napts (reared at permissive temperature), a slight decrease in the extent of branching was observed. Yet, when combined with eag Sh, napts completely reversed the morphological abnormality in eag Sh mutants. No such reversion was observed in parats 1 eag Sh mutants. The endogenous patterns of electrical activity at the neuromuscular junction were analyzed by extracellular recordings in a semi-intact larval preparation. Recordings from wild-type body-wall muscles revealed rhythmic bursts of spikes. In eag Sh mutants, this rhythmic activity was accompanied by or superimposed on periods of strong tonic activity. This abnormal pattern of activity could be partially suppressed by napts in combination with eag Sh.

Item Type: Paper
Additional Information:
Uncontrolled Keywords: Animals Axonal Transport Axons physiology Drosophila genetics physiology Electrophysiology methods Ethyl Methanesulfonate pharmacology Genes, Recessive Horseradish Peroxidase Larva Motor Neurons physiology Muscles innervation Mutation Neuronal Plasticity
Subjects: organism description > animal > insect > Drosophila
Investigative techniques and equipment > electrophysiology
organs, tissues, organelles, cell types and functions > cell types and functions > cell functions > neural plasticity
CSHL Authors:
Communities: CSHL labs > Zhong lab
Depositing User: CSHL Librarian
Date: November 1990
Date Deposited: 30 Mar 2012 17:59
Last Modified: 06 Nov 2017 21:32
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