Factors Influencing Short-term Synaptic Plasticity in the Avian Cochlear Nucleus Magnocellularis:

Journal of Experimental Neuroscience

Jason Tait SanchezQuinones¹ 

关键词: AMPA receptors;    desensitization;    development;    glutamate transporters;    nucleus magnocellularis;    short-term synaptic depression;   

DOI  :  10.4137/JEN.S25472

学科分类：生物科学（综合）

来源: Sage Journals

【 摘 要 】

Defined as reduced neural responses during high rates of activity, synaptic depression is a form of short-term plasticity important for the temporal filtering of sound. In the avian cochlear nucleus magnocellularis (NM), an auditory brainstem structure, mechanisms regulating short-term synaptic depression include pre-, post-, and extrasynaptic factors. Using varied paired-pulse stimulus intervals, we found that the time course of synaptic depression lasts up to four seconds at late-developing NM synapses. Synaptic depression was largely reliant on exogenous Ca2+-dependent probability of presynaptic neurotransmitter release, and to a lesser extent, on the desensitization of postsynaptic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptor (AMPA-R). Interestingly, although extrasynaptic glutamate clearance did not play a significant role in regulating synaptic depression, blocking glutamate clearance at early-developing synapses altered synaptic dynamics, changing responses from depression to facilitation. These results suggest a developmental shift in the relative reliance on pre-, post-, and extrasynaptic factors in regulating short-term synaptic plasticity in NM.

【 授权许可】

CC BY