Zebrafish neuromuscular junction: The power of N

Brehm, Paul; Hua, Wen

doi:10.1016/j.neulet.2019.134503

Cited by 10 publications

(8 citation statements)

References 90 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this study, we provided the first imaging-based evidence supporting the same origin of spontaneous release and RRP ( Fig. 10 ) by applying two genetic tools in intact NMJs of larval zebrafish, which has been intensively used for in vivo analysis of synaptic transmission ( Brehm and Wen, 2019 ).…”

Section: Discussionmentioning

confidence: 91%

“…Here, we used intact NMJs of larval zebrafish, the hallmark of which is a small-sized bouton with a single release site ( Wen et al, 2016b ), amenable to the optical assays of SV recycling. Moreover, the patch-clamp technique applicable to small muscle cells enables the resolution of all quantal events with large current amplitudes ( Brehm and Wen, 2019 ), offering an ideal platform to study spontaneous release. In this study, we generated transgenic (Tg) fish expressing two independent indicators of SV recycling, pHluorin and HaloTag.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spontaneously Recycling Synaptic Vesicles Constitute Readily Releasable Vesicles in Intact Neuromuscular Synapses

et al. 2022

View full text Add to dashboard Cite

Emerging evidence shows that spontaneous synaptic transmission plays crucial roles on neuronal functions through presynaptic molecular mechanisms distinct from that of action potential (AP)-evoked transmission. However, whether the synaptic vesicle (SV) population undergoing the two forms of transmission is segregated remains controversial due in part to the conflicting results observed in cultured neurons. Here we address this issue in intact neuromuscular synapses using transgenic zebrafish larvae expressing two different indicators targeted in the SVs: a pH-sensitive fluorescent protein, pHluorin, and a tag protein, HaloTag. By establishing a quantitative measure of recycled SV fractions, we found that ∼85% of SVs were mobilized by high-frequency AP firings. In contrast, spontaneously recycling SVs were mobilized only from <8% of SVs with a time constant of 45 min at 25°C, although prolonged AP inhibition mobilized an additional population with a delayed onset. The mobilization of the early-onset population was less temperature-sensitive and resistant to tetanus toxin, whereas that of the late-onset population was more sensitive to temperature and was inhibited by tetanus toxin, indicating that prolonged AP inhibition activated a distinct molecular machinery for spontaneous SV fusion. Therefore, the early-onset population limited to <8% was likely the only source of spontaneous release that occurred physiologically. We further showed that this limited population was independent from those reluctant to fuse during AP firing and was used in both the hypertonic stimulation and the immediate phase of AP-evoked releases, thereby matching the characteristics of the readily releasable pool.SIGNIFICANCE STATEMENTSynaptic vesicles (SVs) are divided into functionally distinct pools depending on how they respond to action potential (AP) firing. The origin of SVs used for spontaneous fusion remains enigmatic despite intensive studies in cultured preparations. We addressed this question in intact neuromuscular synapses and provided two findings. First, prolonged AP inhibition activated a distinct population of fusion, which needs to be distinguished from genuine spontaneous fusion arising from a highly limited fraction. Second, the limited fraction observed early in the AP inhibition period exhibited the characteristics of readily releasable pool in the subsequent round of stimulation. Our study revealed that the origin of spontaneous SV fusion is restricted to the readily releasable pool among the SV pools involved in AP-evoked fusion.

show abstract

Section: Discussionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Spontaneously Recycling Synaptic Vesicles Constitute Readily Releasable Vesicles in Intact Neuromuscular Synapses

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Zebrafish NMJ offers some significant advantages over flies in the hunt for mechanisms regulating Pr. Simplicity is provided by the low number of synapses per muscle cell (~15 vs hundreds in fly), the large size of individual synapses which precludes need for super resolution methodology, and the amenability to paired patch clamp Mn-muscle recording (Brehm and Wen, 2019). Additionally, sharing of 1˚ and 2˚ Mn boutons at the same synapse offers the opportunity for side by side interrogation of high and low Pr synapses for differences at the molecular and ultrastructural level.…”

Section: Discussionmentioning

confidence: 99%

“…Labeling with either fluorescently conjugated alpha bungarotoxin (Btx) or postsynaptic rapsyn, tagged with either GCaMP6f or GFP, reveals an en-passant distribution of postsynaptic acetylcholine receptor (AChR) clusters that number ~15 per muscle cell ( Fig. 1A & B) (Wen et al, 2016;Brehm and Wen, 2019). Much evidence points to each cluster as representing an individual synapse formed with the 1˚Mn.…”

Section: Innervation Pattern and Distribution Of 1˚ And 2˚mn Synapsesmentioning

confidence: 99%

Primary and secondary motoneurons use different calcium channel types to control escape and swimming behaviors in zebrafish

Hua

Eckenstein

Weihrauch

et al. 2020

Preprint

Self Cite

View full text Add to dashboard Cite

The escape response and rhythmic swimming in zebrafish are distinct behaviors mediated by two functionally distinct motoneuron (Mn) types. The primary (1˚Mn) type depresses, has a large quantal content (Qc), and a high release probability (Pr). Conversely, the secondary (2˚Mn) type facilitates and has low and variable Qc and Pr. This functional duality matches well the distinct associated behaviors, with the 1˚Mn providing the strong, singular C-bend initiating escape and the 2˚Mn confers weaker, rhythmic contractions. Contributing to these functional distinctions is our identification of P/Q type calcium channels mediating transmitter release in 1˚Mns and N type channels in 2˚Mns. Remarkably, despite these functional and behavioral distinctions, all ~15 individual synapses on each muscle cell are shared by a 1˚Mn bouton and at least one 2˚Mn bouton. This novel blueprint of synaptic sharing provides an efficient way of controlling two different behaviors at the level of a single postsynaptic cell.

show abstract

“…In 1791, Luigi Galvani described the electrical properties of the neuromuscular connection ( Galvani, 1791 ) and Bernard Katz described the quantal nature of neurotransmitter release ( Fatt and Katz, 1952 ) using the neuromuscular junctions of the frog. A more recent example is the in vivo study of synaptic transmission using the NMJ in Zebrafish ( Brehm and Wen, 2019 ). In Drosophila , larval NMJ has been widely studied to understand not only general synaptic development ( Ruiz-Cañada and Budnik, 2006 ; Chou et al, 2020 ) and morphology ( Nijhof et al, 2016 ) but also to investigate the regulation of glutamatergic synapses ( Petersen et al, 1997 ).…”

Section: Introductionmentioning

confidence: 99%

Macros to Quantify Exosome Release and Autophagy at the Neuromuscular Junction of Drosophila Melanogaster

Sanchez-Mirasierra

Hernández-Díaz

Ghimire

et al. 2021

Front. Cell Dev. Biol.

View full text Add to dashboard Cite

Automatic quantification of image parameters is a powerful and necessary tool to explore and analyze crucial cell biological processes. This article describes two ImageJ/Fiji automated macros to approach the analysis of synaptic autophagy and exosome release from 2D confocal images. Emerging studies point out that exosome biogenesis and autophagy share molecular and organelle components. Indeed, the crosstalk between these two processes may be relevant for brain physiology, neuronal development, and the onset/progression of neurodegenerative disorders. In this context, we describe here the macros “Autophagoquant” and “Exoquant” to assess the quantification of autophagosomes and exosomes at the neuronal presynapse of the Neuromuscular Junction (NMJ) in Drosophila melanogaster using confocal microscopy images. The Drosophila NMJ is a valuable model for the study of synapse biology, autophagy, and exosome release. By use of Autophagoquant and Exoquant, researchers can have an unbiased, standardized, and rapid tool to analyze autophagy and exosomal release in Drosophila NMJ.Code available at: https://github.com/IreneSaMi/Exoquant-Autophagoquant

show abstract

Zebrafish neuromuscular junction: The power of N

Cited by 10 publications

References 90 publications

Spontaneously Recycling Synaptic Vesicles Constitute Readily Releasable Vesicles in Intact Neuromuscular Synapses

Spontaneously Recycling Synaptic Vesicles Constitute Readily Releasable Vesicles in Intact Neuromuscular Synapses

Primary and secondary motoneurons use different calcium channel types to control escape and swimming behaviors in zebrafish

Macros to Quantify Exosome Release and Autophagy at the Neuromuscular Junction of Drosophila Melanogaster

Contact Info

Product

Resources

About