Presynaptically silent synapses: spontaneously active terminals without stimulus-evoked release demonstrated in cortical autapses

Journal of Neurophysiology
F KimuraT Tsumoto

Abstract

This study addresses the question of whether synapses that are capable of releasing transmitters spontaneously can also release them in an excitation-dependent manner. For this purpose, whole cell patch recordings were performed for a total of 48 excitatory solitary neurons in a microisland culture to observe excitatory autaptic currents elicited by spontaneous transmitter release as well as by somatic excitation. A somatic Na+-spike, induced in response to a short voltage step, evoked excitatory postsynaptic currents (EPSCs) of various amplitudes through the autapses; in some cases, no response was noticeable. To make sure that the recorded autaptic spontaneous EPSCs (sEPSCs) under a voltage clamp resulted from independent release of transmitters and were not associated with action potentials, sEPSCS in the presence and absence of tetrodotoxin (TTX) were compared in six cells. In the presence of TTX the evoked EPSCs were completely eliminated, whereas the sEPSCs were still observed and the amplitude distribution histograms were statistically not different from those recorded in the absence of TTX. A quantitative analysis of the sEPSCs (presumably miniature EPSCs) showed that the amplitude of stimulus-evoked EPSCs did not corre...Continue Reading

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Citations

Dec 4, 2002·Nature Reviews. Neuroscience·Carlos Vicario-AbejónMenahem Segal
Jun 19, 2001·The Journal of Physiology·K NäglerF W Pfrieger
Apr 7, 2007·Journal of Clinical Neurophysiology : Official Publication of the American Electroencephalographic Society·Waldemar SwierczKevin Staley
Aug 4, 2006·Journal of Neurophysiology·Congyi LuStefano Vicini
May 20, 2020·Frontiers in Synaptic Neuroscience·John M Bekkers
Jan 28, 2005·The European Journal of Neuroscience·Naoki TakadaYukio Komatsu
May 14, 1999·Current Opinion in Neurobiology·A Y Klintsova, W T Greenough

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