Morphological evidence for tracer uptake at the active zones of stimulated frog neuromuscular junction

1983 ◽  
Vol 39 (7) ◽  
pp. 752-753 ◽  
Author(s):  
M. Pecot-Dechavassine
Keyword(s):  
Neuromuscular Junction ◽  
Tracer Uptake ◽  
Morphological Evidence ◽  
Frog Neuromuscular Junction ◽  
Active Zones

scholarly journals Impact of spatiotemporal calcium dynamics within presynaptic active zones on synaptic delay at the frog neuromuscular junction

2018 ◽  
Vol 119 (2) ◽  
pp. 688-699 ◽  
Author(s):  
Anne E. Homan ◽  
Rozita Laghaei ◽  
Markus Dittrich ◽  
Stephen D. Meriney
Keyword(s):  
Neuromuscular Junction ◽  
Neurotransmitter Release ◽  
Vesicle Fusion ◽  
Diffusion Reaction ◽  
Synaptic Delay ◽  
Frog Neuromuscular Junction ◽  
Calcium Dynamics ◽  
Large Role ◽  
Calcium Buffering ◽  
Active Zones

The spatiotemporal calcium dynamics within presynaptic neurotransmitter release sites (active zones, AZs) at the time of synaptic vesicle fusion is critical for shaping the dynamics of neurotransmitter release. Specifically, the relative arrangement and density of voltage-gated calcium channels (VGCCs) as well as the concentration of calcium buffering proteins can play a large role in the timing, magnitude, and plasticity of release by shaping the AZ calcium profile. However, a high-resolution understanding of the role of AZ structure in spatiotemporal calcium dynamics and how it may contribute to functional heterogeneity at an adult synapse is currently lacking. We demonstrate that synaptic delay varies considerably across, but not within, individual synapses at the frog neuromuscular junction (NMJ). To determine how elements of the AZ could contribute to this variability, we performed a parameter search using a spatially realistic diffusion reaction-based computational model of a frog NMJ AZ (Dittrich M, Pattillo JM, King JD, Cho S, Stiles JR, Meriney SD. Biophys J 104: 2751–2763, 2013; Ma J, Kelly L, Ingram J, Price TJ, Meriney SD, Dittrich M. J Neurophysiol 113: 71–87, 2015). We demonstrate with our model that synaptic delay is sensitive to significant alterations in the spatiotemporal calcium dynamics within an AZ at the time of release caused by manipulations of the density and organization of VGCCs or by the concentration of calcium buffering proteins. Furthermore, our data provide a framework for understanding how AZ organization and structure are important for understanding presynaptic function and plasticity. NEW & NOTEWORTHY The structure of presynaptic active zones (AZs) can play a large role in determining the dynamics of neurotransmitter release across many model preparations by influencing the spatiotemporal calcium dynamics within the AZ at the time of vesicle fusion. However, less is known about how different AZ structural schemes may influence the timing of neurotransmitter release. We demonstrate that variations in AZ structure create different spatiotemporal calcium profiles that, in turn, lead to differences in synaptic delay.

221 Presynaptic Ca2+-imaging at the frog neuromuscular junction

1996 ◽  
Vol 25 ◽  
pp. S36 ◽  
Author(s):  
M. Osanai ◽  
S. Suzuki ◽  
N. Suzuki ◽  
K. Kuba ◽  
H. Kijima
Keyword(s):  
Neuromuscular Junction ◽  
Frog Neuromuscular Junction
Sign in / Sign up

Export Citation Format

Share Document