TY - JOUR
T1 - Calcium-triggered exocytosis and endocytosis in an isolated presynaptic cell
T2 - Capacitance measurements in saccular hair cells
AU - Parsons, Thomas D.
AU - Lenzi, David
AU - Almers, Wolfhard
AU - Roberts, William M.
N1 - Funding Information:
We thank T. Bork and E. Schabtach for technical expertise with electron microscopy and B. D.Anson, C. J.Augustine, W. J. Betz, R. H. Chow, J. Coorssen, A. K. Lee, M. Lindau, E. Neher, and G. A. Nevitt for their critical reading of a previous version of this manuscript. This work was supported by an HFSPO Fellowship (T. D. P.), by National Institutes of Health grant NS27142 (W. M. R.), and by a McKnight Scholars Award (W. M. R.).
PY - 1994/10
Y1 - 1994/10
N2 - Depolarization of isolated frog saccular hair cells caused Ca2+-dependent increases in membrane capacitance that we interpret as the fusion of synaptic vesicles with the plasma membrane. During a maintained depolarization to -10 mV, the capacitance increased at a rate corresponding to the fusion of ∼500 vesicles per second at each active zone. Release continued at this high rate for up to 2 s, long enough to exhaust >5 times the number of vesicles initially in close apposition to the plasma membrane at active zones. We therefore propose that hair cells are specialized for rapid replenishment of vesicles at release sites. Upon repolarization to -70 mV, the capacitance returned exponentially (time constant, ∼14 s) to near the prestimulus level in perforated-patch recordings, but not in whole-cell recordings, suggesting that a mobile intracellular factor is required for membrane retrieval.
AB - Depolarization of isolated frog saccular hair cells caused Ca2+-dependent increases in membrane capacitance that we interpret as the fusion of synaptic vesicles with the plasma membrane. During a maintained depolarization to -10 mV, the capacitance increased at a rate corresponding to the fusion of ∼500 vesicles per second at each active zone. Release continued at this high rate for up to 2 s, long enough to exhaust >5 times the number of vesicles initially in close apposition to the plasma membrane at active zones. We therefore propose that hair cells are specialized for rapid replenishment of vesicles at release sites. Upon repolarization to -70 mV, the capacitance returned exponentially (time constant, ∼14 s) to near the prestimulus level in perforated-patch recordings, but not in whole-cell recordings, suggesting that a mobile intracellular factor is required for membrane retrieval.
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U2 - 10.1016/0896-6273(94)90253-4
DO - 10.1016/0896-6273(94)90253-4
M3 - Article
C2 - 7946334
AN - SCOPUS:0028113779
SN - 0896-6273
VL - 13
SP - 875
EP - 883
JO - Neuron
JF - Neuron
IS - 4
ER -