scholarly journals Faculty Opinions recommendation of The EGL-21 carboxypeptidase E facilitates acetylcholine release at Caenorhabditis elegans neuromuscular junctions.

2003 ◽  
Author(s):  
Robert K Herman
Keyword(s):  
Caenorhabditis Elegans ◽  
Acetylcholine Release ◽  
Neuromuscular Junctions ◽  
Carboxypeptidase E

scholarly journals Inhibition of Kv2.1 Potassium Channels by MiDCA1, A Pre-Synaptically Active PLA2-Type Toxin from Micrurus dumerilii carinicauda Coral Snake Venom

Toxins ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 335
Author(s):  
Niklas Schütter ◽  
Yuri Correia Barreto ◽  
Vitya Vardanyan ◽  
Sönke Hornig ◽  
Stephen Hyslop ◽  
...  
Keyword(s):  
Snake Venom ◽  
Potassium Current ◽  
Acetylcholine Release ◽  
Channel Blocker ◽  
Neuromuscular Junctions ◽  
Coral Snake ◽  
Drg Neurons ◽  
Kv Channels ◽  
Heterologous System ◽  
Outward Potassium Current

MiDCA1, a phospholipase A2 (PLA2) neurotoxin isolated from Micrurus dumerilii carinicauda coral snake venom, inhibited a major component of voltage-activated potassium (Kv) currents (41 ± 3% inhibition with 1 μM toxin) in mouse cultured dorsal root ganglion (DRG) neurons. In addition, the selective Kv2.1 channel blocker guangxitoxin (GxTx-1E) and MiDCA1 competitively inhibited the outward potassium current in DRG neurons. MiDCA1 (1 µM) reversibly inhibited the Kv2.1 current by 55 ± 8.9% in a Xenopus oocyte heterologous system. The toxin showed selectivity for Kv2.1 channels over all the other Kv channels tested in this study. We propose that Kv2.1 channel blockade by MiDCA1 underlies the toxin’s action on acetylcholine release at mammalian neuromuscular junctions.

The structure of the ventral nerve cord of Caenorhabditis elegans

1976 ◽  
Vol 275 (938) ◽  
pp. 327-348 ◽  
Keyword(s):  
Caenorhabditis Elegans ◽  
Synaptic Input ◽  
Neuromuscular Junctions ◽  
Nerve Ring ◽  
Motor Neurone ◽  
The Body ◽  
Synaptic Activity ◽  
Linear Sequence ◽  
Motor Neurones ◽  
Longitudinal Fibre

The nervous system of Caenorhabditis elegans is arranged as a series of fibre bundles which run along internal hypodermal ridges. Most of the sensory integration takes place in a ring of nerve fibres which is wrapped round the pharynx in the head. The body muscles in the head are innervated by motor neurones in this nerve ring while those in the lower part of the body are innervated by a set of motor neurones in a longitudinal fibre bundle which joins the nerve ring, the ventral cord. These motor neurones can be put into five classes on the basis of their morphology and synaptic input. At any one point along the cord only one member from each class has neuromuscular junctions. Members of a given class are arranged in a regular linear sequence in the cord and have non-overlapping fields of motor synaptic activity, the transition between fields of adjacent neurones being sharp and well defined. Members of a given class form gap junctions with neighbouring members of the same class but never to motor neurones of another class. Three of the motor neurone classes receive their synaptic input from a set of interneurones coming from the nerve ring. These interneurones can in turn be grouped into four classes and each of the three motor neurone classes receives its synaptic input from a unique combination of interneurone classes. The possible developmental and functional significance of these observations is discussed.

Spontaneous acetylcholine release in mammalian neuromuscular junctions

1997 ◽  
Vol 273 (6) ◽  
pp. C1835-C1841 ◽  
Author(s):  
Adriana Losavio ◽  
S. Muchnik
Keyword(s):  
Neuromuscular Junction ◽  
Acetylcholine Release ◽  
Neuromuscular Junctions ◽  
The Other ◽  
Nerve Terminals ◽  
Transmitter Secretion ◽  
Other Hand ◽  
Voltage Dependent ◽  
Intracellular Ca ◽  
Lower Effect

Spontaneous secretion of the neurotransmitter acetylcholine in mammalian neuromuscular synapsis depends on the Ca2+ content of nerve terminals. The Ca2+ electrochemical gradient favors the entry of this cation. We investigated the possible involvement of three voltage-dependent Ca2+ channels (VDCC) (L-, N-, and P/Q-types) on spontaneous transmitter release at the rat neuromuscular junction. Miniature end-plate potential (MEPP) frequency was clearly reduced by 5 μM nifedipine, a blocker of the L-type VDCC, and to a lesser extent by the N-type VDCC blocker, ω-conotoxin GVIA (ω-CgTx, 5 μM). On the other hand, nifedipine and ω-CgTx had no effect on K+-induced transmitter secretion. ω-Agatoxin IVA (100 nM), a P/Q-type VDCC blocker, prevents acetylcholine release induced by K+ depolarization but failed to affect MEPP frequency in basal conditions. These results suggest that in the mammalian neuromuscular junction Ca2+ enters nerve terminals through at least three different channels, two of them (L- and N-types) mainly related to spontaneous acetylcholine release and the other (P/Q-type) mostly involved in depolarization-induced neurotransmitter release. Ca2+-binding molecule-related spontaneous release apparently binds Ca2+ very rapidly and would probably be located very close to Ca2+ channels, since the fast Ca2+ chelator (BAPTA-AM) significantly reduced MEPP frequency, whereas EGTA-AM, exhibiting slower kinetics, had a lower effect. The increase in MEPP frequency induced by exposing the preparation to hypertonic solutions was affected by neither external Ca2+concentration nor L-, N-, and P/Q-type VDCC blockers, indicating that extracellular Ca2+ is not necessary to produce hyperosmotic neurosecretion. On the other hand, MEPP frequency was diminished by BAPTA-AM and EGTA-AM to the same extent, supporting the view that hypertonic response is promoted by “bulk” intracellular Ca2+concentration increases.

scholarly journals Ultrafast endocytosis at Caenorhabditis elegans neuromuscular junctions

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Shigeki Watanabe ◽  
Qiang Liu ◽  
M Wayne Davis ◽  
Gunther Hollopeter ◽  
Nikita Thomas ◽  
...  
Keyword(s):  
Caenorhabditis Elegans ◽  
Motor Neurons ◽  
Synaptic Vesicles ◽  
Neuromuscular Junctions ◽  
Light Stimulus ◽  
Single Stimulus ◽  
Vesicle Recycling ◽  
Ultrastructural Studies ◽  
Millisecond Time Scale ◽  
Intense Stimulation

Synaptic vesicles can be released at extremely high rates, which places an extraordinary demand on the recycling machinery. Previous ultrastructural studies of vesicle recycling were conducted in dissected preparations using an intense stimulation to maximize the probability of release. Here, a single light stimulus was applied to motor neurons in intact Caenorhabditis elegans nematodes expressing channelrhodopsin, and the animals rapidly frozen. We found that docked vesicles fuse along a broad active zone in response to a single stimulus, and are replenished with a time constant of about 2 s. Endocytosis occurs within 50 ms adjacent to the dense projection and after 1 s adjacent to adherens junctions. These studies suggest that synaptic vesicle endocytosis may occur on a millisecond time scale following a single physiological stimulus in the intact nervous system and is unlikely to conform to current models of endocytosis.

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