scholarly journals Activity-dependent control of bulk endocytosis by protein dephosphorylation in central nerve terminals

2007 ◽  
Vol 585 (3) ◽  
pp. 687-691 ◽  
Author(s):  
Emma L. Clayton ◽  
Gareth J. O. Evans ◽  
Michael A. Cousin
Keyword(s):  
Nerve Terminals ◽  
Protein Dephosphorylation ◽  
Activity Dependent

scholarly journals Rab3A Is Involved in Transport of Synaptic Vesicles to the Active Zone in Mouse Brain Nerve Terminals

2001 ◽  
Vol 12 (10) ◽  
pp. 3095-3102 ◽  
Author(s):  
A.G. Miriam Leenders ◽  
Fernando H. Lopes da Silva ◽  
Wim E.J.M. Ghijsen ◽  
Matthijs Verhage
Keyword(s):  
Active Zone ◽  
Synaptic Vesicles ◽  
Nerve Terminals ◽  
Null Mutant ◽  
Rab Protein ◽  
Fusion Probability ◽  
Intracellular Compartments ◽  
Null Mutant Mice ◽  
Dependent Transport ◽  
Activity Dependent

The rab family of GTP-binding proteins regulates membrane transport between intracellular compartments. The major rab protein in brain, rab3A, associates with synaptic vesicles. However, rab3A was shown to regulate the fusion probability of synaptic vesicles, rather than their transport and docking. We tested whether rab3A has a transport function by analyzing synaptic vesicle distribution and exocytosis in rab3A null-mutant mice. Rab3A deletion did not affect the number of vesicles and their distribution in resting nerve terminals. The secretion response upon a single depolarization was also unaffected. In normal mice, a depolarization pulse in the presence of Ca2+ induces an accumulation of vesicles close to and docked at the active zone (recruitment). Rab3A deletion completely abolished this activity-dependent recruitment, without affecting the total number of vesicles. Concomitantly, the secretion response in the rab3A-deficient terminals recovered slowly and incompletely after exhaustive stimulation, and the replenishment of docked vesicles after exhaustive stimulation was also impaired in the absence of rab3A. These data indicate that rab3A has a function upstream of vesicle fusion in the activity-dependent transport of synaptic vesicles to and their docking at the active zone.

Dynamical Mean Field Model of a Neural-Glial Mass

2010 ◽  
Vol 22 (4) ◽  
pp. 969-997 ◽  
Author(s):  
Roberto C. Sotero ◽  
Ramón Martínez-Cancino
Keyword(s):  
Differential Equations ◽  
Field Model ◽  
Mean Field ◽  
Field Approximation ◽  
Presynaptic Terminal ◽  
Mean Field Approximation ◽  
Nerve Terminals ◽  
Mean Field Model ◽  
Wide Range ◽  
Activity Dependent

Our goal is to model the behavior of an ensemble of interacting neurons and astrocytes (the neural-glial mass). For this, a model describing N tripartite synapses is proposed. Each tripartite synapse consists of presynaptic and postsynaptic nerve terminals, as well as the synaptically associated astrocytic microdomain, and is described by a system of 13 stochastic differential equations. Then, by applying the dynamical mean field approximation (DMA) (Hasegawa, 2003a , 2003b ) the system of 13N equations is reduced to 13(13 + 2) = 195 deterministic differential equations for the means and the second-order moments of local and global variables. Simulations are carried out for studying the response of the neural-glial mass to external inputs applied to either the presynaptic terminals or the astrocytes. Three cases were considered: the astrocytes influence only the presynaptic terminal, only the postsynaptic terminal, or both the presynaptic and postsynaptic terminals. As a result, a wide range of responses varying from singles spikes to train of spikes was evoked on presynaptic and postsynaptic terminals. The experimentally observed phenomenon of spontaneous activity in astrocytes was replicated on the neural-glial mass. The model predicts that astrocytes can have a strong and activity-dependent influence on synaptic transmission. Finally, simulations show that the dynamics of astrocytes influences the synchronization ratio between neurons, predicting a peak in the synchronization for specific values of the astrocytes’ parameters.

Activity-dependent neurotransmitter release kinetics: correlation with changes in morphological distributions of small and large vesicles in central nerve terminals

1999 ◽  
Vol 11 (12) ◽  
pp. 4269-4277 ◽  
Author(s):  
A. G. Miriam Leenders ◽  
Greet Scholten ◽  
Victor M. Wiegant ◽  
Fernando H. Lopes Da Silva ◽  
Wim E. J. M. Ghijsen
Keyword(s):  
Neurotransmitter Release ◽  
Release Kinetics ◽  
Nerve Terminals ◽  
Activity Dependent

scholarly journals Dynamin phosphorylation controls optimization of endocytosis for brief action potential bursts

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Moritz Armbruster ◽  
Mirko Messa ◽  
Shawn M Ferguson ◽  
Pietro De Camilli ◽  
Timothy A Ryan
Keyword(s):  
Steady State ◽  
Kinetic Parameter ◽  
Action Potential ◽  
Nerve Terminals ◽  
Acceleration Phase ◽  
Action Potential Firing ◽  
Physiological Temperature ◽  
Rich Domain ◽  
Potential Firing ◽  
Activity Dependent

Modulation of synaptic vesicle retrieval is considered to be potentially important in steady-state synaptic performance. Here we show that at physiological temperature endocytosis kinetics at hippocampal and cortical nerve terminals show a bi-phasic dependence on electrical activity. Endocytosis accelerates for the first 15–25 APs during bursts of action potential firing, after which it slows with increasing burst length creating an optimum stimulus for this kinetic parameter. We show that activity-dependent acceleration is only prominent at physiological temperature and that the mechanism of this modulation is based on the dephosphorylation of dynamin 1. Nerve terminals in which dynamin 1 and 3 have been replaced with dynamin 1 harboring dephospho- or phospho-mimetic mutations in the proline-rich domain eliminate the acceleration phase by either setting endocytosis at an accelerated state or a decelerated state, respectively.

scholarly journals Activity-Dependent Plasticity of Transmitter Release from Nerve Terminals in Rat Fast and Slow Muscles

2003 ◽  
Vol 23 (28) ◽  
pp. 9340-9348 ◽  
Author(s):  
Brian Reid ◽  
Vladimir N. Martinov ◽  
Arild Njå ◽  
Terje Lømo ◽  
Guy S. Bewick
Keyword(s):  
Transmitter Release ◽  
Nerve Terminals ◽  
Dependent Plasticity ◽  
Fast And Slow Muscles ◽  
Activity Dependent

scholarly journals The Role of GSK3 in Presynaptic Function

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Karen Janet Smillie ◽  
Michael Alan Cousin
Keyword(s):  
Synaptic Vesicles ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase 3 ◽  
Nerve Terminals ◽  
The Past ◽  
Presynaptic Function ◽  
Signalling Cascades ◽  
Synaptic Failure ◽  
Activity Dependent

The past ten years of research have identified a number of key roles for glycogen synthase kinase 3 (GSK3) at the synapse. In terms of presynaptic physiology, critical roles for GSK3 have been revealed in the growth and maturation of the nerve terminal and more recently a key role in the control of activity-dependent bulk endocytosis of synaptic vesicles. This paper will summarise the major roles assigned to GSK3 in both immature and mature nerve terminals, the substrates GSK3 phosphorylates to exert its action, and how GSK3 activity is regulated by different presynaptic signalling cascades. The number of essential roles for GSK3, coupled with the numerous signalling cascades all converging to regulate its activity, suggests that GSK3 is a key integrator of multiple inputs to modulate the strength of neurotransmission. Modulation of these pathways may point to potential mechanisms to overcome synaptic failure in neurodegenerative disorders such as Alzheimer's disease.

Sign in / Sign up

Export Citation Format

Share Document