1. EGTA inhibition of release probability near a VGCC cluster.
EGTA inhibition of release probability near a VGCC cluster. A, Contour spatial maps of 50% EGTA inhibition of Pv for clusters of 4, 12, and 28 open VGCCs. d1 and d2 are distances from the location where 50% inhibition of Pv was observed to the center of gravity of the VGCC cluster or to the closest perimeter VGCC, respectively. The NND of the VGCCs was 30 nm. Vesicular release was evoked by VGCC opening of 0.3 pA for 0.2 ms (red; similar to Ca2+ influx by APs), 0.3 pA for 1 ms (black; same as Fig. 1 and 6), or pA for 20 ms (green). Diagram depicts the spatial arrangement of the VGCC cluster and Ca2+ sensor associated with a synaptic vesicle. Cross indicates the center of gravity of the VGCC cluster. B, Inhibitory effect of EGTA on Pv as a function of distance from the Ca2+ sensor to the center of the VGCC cluster (d1). Bottom, d1 exhibiting 50% EGTA inhibition of Pv as a function of number of VGCCs in the cluster. C, Same as B but for the distance between the Ca2+ sensor to the nearest VGCC (cluster perimeter to sensor distance, d2). D, Pv at d2 = 30 nm as a function of number of VGCCs in the cluster.
Yukihiro Nakamura et al. J. Neurosci. 2018;38:
©2018 by Society for Neuroscience