Action potential evoked transmitter release in central synapses: insights from the developing calyx of Held.
Chemical synapses are the fundamental units that mediate communication between neurons in the mammalian brain. In contrast to the enormous progress made in mapping out postsynaptic contributions of receptors, scaffolding structures and receptor trafficking to synaptic transmission and plasticity, the small size of nerve terminals has largely precluded direct analyses of presynaptic modulation of excitability and transmitter release in central synapses. Recent studies performed in accessible synapses such as the calyx of Held, a giant axosomatic synapse in the sound localization circuit of the auditory brainstem, have provided tremendous insights into how central synapses regulate the dynamic gain range of synaptic transmission. This review will highlight experimental evidence that resolves several long-standing issues with respect to intricate interplays between the waveform of action potentials, Ca2+ currents and transmitter release and further conceptualize their relationships in a physiological context with theoretical models of the spatial organization of voltage-gated Ca2+ channels and synaptic vesicles at release sites.
Wang
Lu-Yang
LY
Program for Neurosciences and Mental Health, The Hospital for Sick Children and Department of Physiology, University of Toronto, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada. luyang.wang@utoronto.ca
Fedchyshyn
Michael J
MJ
Yang
Yi-Mei
YM
D000200:Action Potentials / Q000502:physiology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D009473:Neuronal Plasticity / Q000502:physiology; D018377:Neurotransmitter Agents / Q000378:metabolism*; D013569:Synapses / Q000502:physiology*
D018377:Neurotransmitter Agents; D002118:Calcium