scholarly journals Contribution of Postsynaptic GluD2 to Presynaptic R-type Ca2+ Channel Function, Glutamate Release and Long-term Potentiation at Parallel Fiber to Purkinje Cell Synapses

2013 ◽  
Vol 12 (5) ◽  
pp. 657-666 ◽  
Author(s):  
Manami Yamashita ◽  
Shin-ya Kawaguchi ◽  
Tomoo Hirano
Keyword(s):  
Purkinje Cell ◽  
Glutamate Release ◽  
Long Term Potentiation ◽  
Parallel Fiber ◽  
Channel Function ◽  
Term Potentiation

scholarly journals Silent synapses: what are they telling us about long-term potentiation?

2003 ◽  
Vol 358 (1432) ◽  
pp. 727-733 ◽  
Author(s):  
Dimitri M. Kullmann
Keyword(s):  
Ampa Receptors ◽  
Hippocampal Neurons ◽  
Glutamate Release ◽  
Postsynaptic Density ◽  
Long Term Potentiation ◽  
Silent Synapses ◽  
Term Potentiation ◽  
Silent Synapse ◽  
Cortical Synapses

At several cortical synapses glutamate release events can be mediated exclusively by NMDA receptors, with no detectable contribution from AMPA receptors. This observation was originally made by comparing the trial-to-trial variability of the two components of synaptic signals evoked in hippocampal neurons, and was subsequently confirmed by recording apparently pure NMDA receptor-mediated EPSCs with stimulation of small numbers of axons. It has come to be known as the ‘silent synapse’ phenomenon, and is widely assumed to be caused by the absence of functional AMPA receptors, which can, however, be recruited into the postsynaptic density by long-term potentiation (LTP) induction. Thus, it provides an important impetus for relating AMPA receptor trafficking mechanisms to the expression of LTP, a theme that is taken up elsewhere in this issue. This article draws attention to several findings that call for caution in identifying silent synapses exclusively with synapses without AMPA receptors. In addition, it attempts to identify several missing pieces of evidence that are required to show that unsilencing of such synapses is entirely accounted for by insertion of AMPA receptors into the postsynaptic density. Some aspects of the early stages of LTP expression remain open to alternative explanations.

scholarly journals Expression mechanisms underlying long-term potentiation: a postsynaptic view

2003 ◽  
Vol 358 (1432) ◽  
pp. 721-726 ◽  
Author(s):  
Roger A. Nicoll
Keyword(s):  
Nmda Receptor ◽  
Ampa Receptors ◽  
Glutamate Release ◽  
Glutamate Transporter ◽  
Long Term Potentiation ◽  
Receptor Activation ◽  
Covalent Modification ◽  
Term Potentiation ◽  
Expression Mechanism

This review summarizes the various experiments that have been carried out to determine if the expression of long-term potentiation (LTP), in particular N -methyl-D-aspartate (NMDA) receptor-dependent LTP, is presynaptic or postsynaptic. Evidence for a presynaptic expression mechanism comes primarily from experiments reporting that glutamate overflow is increased during LTP and from experiments showing that the failure rate decreases during LTP. However, other experimental approaches, such as monitoring synaptic glutamate release by recording astrocytic glutamate transporter currents, have failed to detect any change in glutamate release during LTP. In addition, the discovery of silent synapses, in which LTP rapidly switches on α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor function at NMDA-receptor-only synapses, provides a postsynaptic mechanism for the decrease in failures during LTP. It is argued that the preponderance of evidence favours a postsynaptic expression mechanism, whereby NMDA receptor activation results in the rapid recruitment of AMPA receptors as well as a covalent modification of synaptic AMPA receptors.

scholarly journals Long-term potentiation in the anterior cingulate cortex and chronic pain

2014 ◽  
Vol 369 (1633) ◽  
pp. 20130146 ◽  
Author(s):  
Min Zhuo
Keyword(s):  
Chronic Pain ◽  
Anterior Cingulate Cortex ◽  
Dorsal Horn ◽  
Glutamate Release ◽  
Cingulate Cortex ◽  
Long Term Potentiation ◽  
Anterior Cingulate ◽  
Spinal Cord Dorsal Horn ◽  
Term Potentiation

Glutamate is the primary excitatory transmitter of sensory transmission and perception in the central nervous system. Painful or noxious stimuli from the periphery ‘teach’ humans and animals to avoid potentially dangerous objects or environments, whereas tissue injury itself causes unnecessary chronic pain that can even last for long periods of time. Conventional pain medicines often fail to control chronic pain. Recent neurobiological studies suggest that synaptic plasticity taking place in sensory pathways, from spinal dorsal horn to cortical areas, contributes to chronic pain. Injuries trigger long-term potentiation of synaptic transmission in the spinal cord dorsal horn and anterior cingulate cortex, and such persistent potentiation does not require continuous neuronal activity from the periphery. At the synaptic level, potentiation of excitatory transmission caused by injuries may be mediated by the enhancement of glutamate release from presynaptic terminals and potentiated postsynaptic responses of AMPA receptors. Preventing, ‘erasing’ or reducing such potentiation may serve as a new mechanism to inhibit chronic pain in patients in the future.

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