1. Fast Ca2+ Buffer-Dependent Reliable but Plastic Transmission at Small CNS Synapses Revealed by Direct Bouton Recording 
Shin-ya Kawaguchi, Takeshi Sakaba 
Cell Reports 
Volume 21, Issue 12, Pages (December 2017)
DOI: /j.celrep
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2. Cell Reports 2017 21, 3338-3345DOI: (10.1016/j.celrep.2017.11.072)
Copyright © 2017 The Author(s) Terms and Conditions

3. Figure 1
Direct Recording of Synaptic Vesicle Exocytosis from a GC Bouton
(A) Fluorescent image of paired recordings from an EGFP-labeled GC and a postsynaptic inhibitory interneuron labeled with CF633.
(B) Representative EPSCs at a GC-interneuron pair (shown in A) triggered by presynaptic somatic firing caused by voltage pulses to 0 mV for 1 ms. Red trace is the average of individual trials shown in gray (60 traces).
(C) Image of EGFP-labeled GC bouton recording. From a small varicosity (∼1 μm, marked by an arrowhead), patch-clamp recording was performed.
(D) Representative traces of presynaptic ICa2+ and Cm changes upon various durations (2, 5, 10, 20, or 50 ms) of depolarization pulses to 0 mV.
(E) Cm increases upon altered durations of depolarization. n = 12 boutons. Data are represented as mean ± SEM.
(F) Left: averaged traces of ICa2+ (n = 5 cells) upon 50 ms depolarization before and after sequential applications of ω-agatoxin-IVA, ω-conotoxin-GVIA, and Ni2+. Right: isolated subtype-specific ICa2+ obtained by subtraction of traces.
(G) Averaged Cm changes (n = 4 cells) before and after the sequential applications of Ca2+ channel blockers.
See also Figure S1.
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4. Figure 2
Kinetic Analysis of Vesicular Release by Paired Recordings from a Presynaptic GC Bouton and a Postsynaptic Interneuron
(A) Light field (left) and EGFP fluorescence (right) images for paired recordings from a presynaptic GC bouton (yellow arrowheads) and a postsynaptic inhibitory interneuron soma.
(B) Depolarization-induced ICa2+, Cm changes, EPSCs in the presence of CTZ, and the time course of cumulative vesicle releases calculated by deconvolution of EPSC traces.
(C) Estimated number of vesicles released upon various depolarization pulses (at 50 ms after depolarization) was plotted against the Cm increase in the presence or absence of CTZ. The gray line represents a relation based on a single vesicle capacitance as 0.1 fF. n = 6 (+CTZ) and 10 cells (−CTZ). Data are represented as mean ± SEM.
(D) Averaged time courses of cumulative release (top) and release rate (bottom, from 5 boutons) upon 50 ms depolarization pulses to the presynaptic bouton. Dotted red line is an exponential curve (23 vesicles, τ = 7 ms) plus a line (1.4 vesicles/ms).
See also Figure S2.
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5. Figure 3
High Sensitivity of Transmitter Release to Ca2+ Buffers in a GC Bouton
(A) Cm increase (measured 50–100 ms after depolarization) in the presence of various Ca2+ chelators. n = 12 (control: 0.5 mM EGTA), 6 (0.1 mM BAPTA), 7 (0.5 mM BAPTA), and 11 (5 mM EGTA).
(B) Kinetics of vesicle release during depolarization (to 0 mV) in the presence of various Ca2+ buffer conditions. n = 5 (control: 0.5 mM EGTA), 5 (0.1 mM BAPTA), 6 (0.5 mM BAPTA), and 6 (5 mM EGTA). The release starts ∼2 ms after the onset of depolarization pulse because of slow ICa2+ activation upon depolarization to 0 mV (Figure S1).
(C) Voltage commands, with various amplitudes of APs, and the representative presynaptic ICa2+ and postsynaptic EPSCs.
(D and E) Amplitudes of ICa2+ (D) and estimated numbers of released vesicles (E) were plotted against the relative AP amplitudes with various Ca2+ chelators.
(F) Relations between released vesicle number and amplitude of ICa2+. Data are represented as mean ± SEM.
See also Figure S3.
Cell Reports  , DOI: ( /j.celrep )
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6. Figure 4
Short-Term Synaptic Facilitation Relies on Fast Ca2+ Buffer in a GC Bouton
(A) Voltage commands for the AP train (100 Hz) with various amplitudes and representative ICa2+ traces.
(B and C) Representative EPSCs (B, averaged from several traces for each) and averaged cumulative plot of the release events (C) in response to the AP train (shown in A) with various presynaptic Ca2+ buffers.
(D) Numbers of released vesicles with various Ca2+ buffers. n = 5 pairs (0.5 mM EGTA, 0.1 mM BAPTA), 6 pairs (0.5 mM BAPTA), and 8 pairs (5 mM EGTA). For comparison, representative EPSC traces (B) obtained by somatic recordings from a pair (with 12 synaptic contacts), the averaged cumulative release plot (C), and the number of released vesicles at a single synaptic contact (D, n = 5 pairs) are shown at bottom. Data are represented as mean ± SEM.
See also Figure S4.
Cell Reports  , DOI: ( /j.celrep )
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