Modulation of neuromuscular synapses and contraction inDrosophila3rd instar larvae

Abstract

Over the past four decades, Drosophila melanogaster has become an increasingly important model system for studying the modulation of chemical synapses and muscle contraction by cotransmitters and neurohormones. This review describes how advantages provided by Drosophila have been utilized to investigate synaptic modulation, and it discusses key findings from investigations of cotransmitters and neurohormones that act on body wall muscles of 3rd instar Drosophila larvae. These studies have contributed much to our understanding of how neuromuscular systems are modulated by neuropeptides and biogenic amines, but there are still gaps in relating these peripheral modulatory effects to behavior. ARTICLE HISTORY

GnRH-Related Neurohormones in the Fruit Fly Drosophila Melanogaster

“…Like vertebrates, insects, including Drosophila , have numerous neuropeptide eliciting hormonal signals and complex signaling networks [ 34 , 35 , 36 , 37 ]. AKH is a peptidic neurohormone of 8–10 amino acid residues synthesized in the corpus cardiacum, which is part of the ring gland [ 24 ].…”

Intensity coded octopaminergic modulation of aversive crawling behavior inDrosophila melanogasterlarvae

“…Importantly, the effects are cell selective and correlate with the distribution of octopamine receptors (El-Kholy et al, 2015) on different muscles within each body wall segment. Hence, octopamine has an important role as neuromodulator and a great potential impact on the coordination of different transversal and longitudinal muscles important for crawling activity (Ormerod et al, 2018). Fox et al (2006) revealed that mutants (Tβh nM18 ) with a reduced level of octopamine and an increased level of tyramine exhibit fewer rhythmic neuronal bursts in motoneurons associated with body wall contraction waves.…”

“…Octopamine mutants are also more vulnerable to environmental stress (Chentsova et al, 2002) while wildtype flies increase octopamine levels in response (Hirashima et al, 2000) suggesting that the effects are not only local but also systemic adapting the whole system to higher performances. Future studies on the effects of octopamine release like the coordination of muscles and body wall segments in the periphery, as well as central effects and systemic adaptation are needed to fully evaluate the specific role of octopamine and other neuromodulators and neuropeptides in larval and adult behavior (Ormerod et al, 2018).…”

Excitation-contraction coupling and its relation to synaptic dysfunction in Drosophila

“…Drosophila melanogaster has become a popular system to dissect and explore the composition and regulation of many of these components, including CPGs (Clark et al, 2018; Song et al, 2007), interneurons (Hasegawa et al, 2016), and sensory neurons (Singhania and Grueber, 2014; Song et al, 2007). Despite these efforts, studies directly examining the role of excitation-contraction coupling in locomotion are limited (Lehmann and Dickinson, 1997; Ormerod et al, 2018, 2016, 2015).…”

“…Three different motoneuron subtypes are present: type I, which releases glutamate from synaptic vesicles; type II, which predominantly contain large dense core vesicles (DCVs); and type III, which innervate muscle 12 and release insulin-like peptides (Budnik, 1996; Hoang and Chiba, 2001). The neuromuscular junction (NMJ) is a critical site of plasticity and can be controlled by neuromodulators released directly from motoneuron terminals or centrally into the open circulator system as hormones (Milakovic et al, 2014; Ormerod et al, 2018, 2013). Type I motor neurons are rhythmically active during waves of muscle contractions underlying forward and reverse locomotion (Newman et al, 2017).…”