scholarly journals BDNF increases release probability and the size of a rapidly recycling vesicle pool within rat hippocampal excitatory synapses

2006 ◽  
Vol 574 (3) ◽  
pp. 787-803 ◽  
Author(s):  
William J. Tyler ◽  
Xiao-lei Zhang ◽  
Kenichi Hartman ◽  
Jochen Winterer ◽  
Wolfgang Muller ◽  
...  
Keyword(s):  
Excitatory Synapses ◽  
Release Probability ◽  
Vesicle Pool

scholarly journals APP Homodimers Transduce an Amyloid-β-Mediated Increase in Release Probability at Excitatory Synapses

Cell Reports ◽  
2014 ◽  
Vol 7 (5) ◽  
pp. 1560-1576 ◽  
Author(s):  
Hilla Fogel ◽  
Samuel Frere ◽  
Oshik Segev ◽  
Shashank Bharill ◽  
Ilana Shapira ◽  
...  
Keyword(s):  
Amyloid Β ◽  
Excitatory Synapses ◽  
Release Probability

The Pool of Fast Releasing Vesicles Is Augmented by Myosin Light Chain Kinase Inhibition at the Calyx of Held Synapse

2008 ◽  
Vol 99 (4) ◽  
pp. 1810-1824 ◽  
Author(s):  
Geetha Srinivasan ◽  
Jun Hee Kim ◽  
Henrique von Gersdorff
Keyword(s):  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Regulatory Protein ◽  
Developmental Studies ◽  
Calyx Of Held ◽  
Release Probability ◽  
Readily Releasable Pool ◽  
Action Potential Waveform ◽  
Vesicle Pool

Synaptic strength is determined by release probability and the size of the readily releasable pool of docked vesicles. Here we describe the effects of blocking myosin light chain kinase (MLCK), a cytoskeletal regulatory protein thought to be involved in myosin-mediated vesicle transport, on synaptic transmission at the mouse calyx of Held synapse. Application of three different MLCK inhibitors increased the amplitude of the early excitatory postsynaptic currents (EPSCs) in a stimulus train, without affecting the late steady-state EPSCs. A presynaptic locus of action for MLCK inhibitors was confirmed by an increase in the frequency of miniature EPSCs that left their average amplitude unchanged. MLCK inhibition did not affect presynaptic Ca2+ currents or action potential waveform. Moreover, Ca2+ imaging experiments showed that [Ca2+]i transients elicited by 100-Hz stimulus trains were not altered by MLCK inhibition. Studies using high-frequency stimulus trains indicated that MLCK inhibitors increase vesicle pool size, but do not significantly alter release probability. Accordingly, when AMPA-receptor desensitization was minimized, EPSC paired-pulse ratios were unaltered by MLCK inhibition, suggesting that release probability remains unaltered. MLCK inhibition potentiated EPSCs even when presynaptic Ca2+ buffering was greatly enhanced by treating slices with EGTA-AM. In addition, MLCK inhibition did not affect the rate of recovery from short-term depression. Finally, developmental studies revealed that EPSC potentiation by MLCK inhibition starts at postnatal day 5 (P5) and remains strong during synaptic maturation up to P18. Overall, our data suggest that MLCK plays a crucial role in determining the size of the pool of synaptic vesicles that undergo fast release at a CNS synapse.

Synaptic organization of the gustatory NST

1994 ◽  
Vol 52 ◽  
pp. 150-151
Author(s):  
M. C. Whitehead
Keyword(s):  
Central Nervous System ◽  
Dendritic Spines ◽  
Fundamental Problem ◽  
Cell Types ◽  
Brain Regions ◽  
Excitatory Synapses ◽  
Solitary Tract ◽  
Synaptic Organization ◽  
Synaptic Junctions ◽  
Afferent Terminals

A fundamental problem in taste research is to determine how gustatory signals are processed and disseminated in the mammalian central nervous system. An important first step toward understanding information processing is the identification of cell types in the nucleus of the solitary tract (NST) and their synaptic relationships with oral primary afferent terminals. Facial and glossopharyngeal (LIX) terminals in the hamster were labelled with HRP, examined with EM, and characterized as containing moderate concentrations of medium-sized round vesicles, and engaging in asymmetrical synaptic junctions. Ultrastructurally the endings resemble excitatory synapses in other brain regions.Labelled facial afferent endings in the RC subdivision synapse almost exclusively with distal dendrites and dendritic spines of NST cells. Most synaptic relationships between the facial synapses and the dendrites are simple. However, 40% of facial endings engage in complex synaptic relationships within glomeruli containing unlabelled axon endings particularly ones termed "SP" endings. SP endings are densely packed with small, pleomorphic vesicles and synapse with both the facial endings and their postsynaptic dendrites by means of nearly symmetrical junctions.

Three-dimensional structure of dendritic spines, neuronal specializations that impart both stability and flexibility to synaptic function

1993 ◽  
Vol 51 ◽  
pp. 92-93
Author(s):  
Kristen M. Harris
Keyword(s):  
Dendritic Spines ◽  
Three Dimensional ◽  
Synaptic Function ◽  
Dimensional Structure ◽  
Excitatory Synapses ◽  
Concept Of Function ◽  
Section Electron ◽  
High Quality Information ◽  
The Central Nervous System ◽  
Mathematical Analyses

Dendritic spines are the tiny protrusions that stud the surface of many neurons and they are the location of over 90% of all excitatory synapses that occur in the central nervous system. Their small size and variable shapes has in large part made detailed study of their structure refractory to conventional light microscopy and single section electron microscopy (EM). Yet their widespread occurrence and likely involvement in learning and memory has motivated extensive efforts to obtain quantitative descriptions of spines in both steady state and dynamic conditions. Since the seminal mathematical analyses of D’Arcy Thompson, the power of establishing quantitatively key parameters of structure has become recognized as a foundation of successful biological inquiry. For dendritic spines highly precise determinations of structure and its variation are proving themselves as the kingpin for establishing a valid concept of function. The recent conjunction of high quality information about the structure, function, and theoretical implications of dendritic spines has produced a flurry of new considerations of their role in synaptic transmission.

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