Dynamics of volume‐averaged intracellular Ca2+ in a rat CNS nerve terminal during single and repetitive voltage‐clamp depolarizations

摘要

Key points class="unordered" style="list-style-type:disc" id="tjp12145-list-0001">The intracellular concentration of free calcium ions ([Ca²⁺]i) in a nerve terminal controls both transmitter release and synaptic plasticity.The rapid triggering of transmitter release depends on the local micro‐ or nanodomain of highly elevated [Ca²⁺]i in the vicinity of open voltage‐gated Ca²⁺ channels, whereas short‐term synaptic plasticity is often controlled by global changes in residual [Ca²⁺]i, averaged over the whole nerve terminal volume.Here we describe dynamic changes of such global [Ca²⁺]i in the calyx of Held – a giant mammalian glutamatergic nerve terminal, which is particularly suited for biophysical studies.We provide quantitative data on Ca²⁺ inflow, Ca²⁺ buffering and Ca²⁺ clearance.These data allow us to predict changes in [Ca²⁺]i in the nerve terminal in response to a wide range of stimulus protocols at high temporal resolution and provide a basis for the modelling of short‐term plasticity of glutamatergic synapses.