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Non‐calyceal excitatory inputs mediate low fidelity synaptic transmission in rat auditory brainstem slices
Author(s) -
Hamann Martine,
Billups Brian,
Forsythe Ian D.
Publication year - 2003
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.2003.03017.x
Subject(s) - excitatory postsynaptic potential , neuroscience , postsynaptic potential , trapezoid body , postsynaptic current , ampa receptor , neurotransmission , inhibitory postsynaptic potential , synapse , nmda receptor , chemistry , biology , nucleus , receptor , biochemistry
Principal neurons of the medial nucleus of the trapezoid body (MNTB) receive a synaptic input from a single giant calyx terminal that generates a fast‐rising, large excitatory postsynaptic current (EPSC), each of which are supra‐threshold for postsynaptic action potential generation. Here, we present evidence that MNTB principal neurons receive multiple excitatory synaptic inputs generating slow‐rising, small EPSCs that are also capable of triggering postsynaptic action potentials but are of non‐calyceal origin. Both calyceal and non‐calyceal EPSCs are mediated by α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionate (AMPA) and N ‐methyl‐ d ‐aspartate (NMDA) receptor activation; however, the NMDA receptor‐mediated response is proportionally larger at the non‐calyceal synapses. Non‐calyceal synapses generate action potentials in MNTB principal neurons with a longer latency and a lower reliability than the large calyceal input. They constitute an alternative low fidelity synaptic input to the fast and secure relay transmission via the calyx of Held synapse.