TY - JOUR
T1 - A highly Ca2+-sensitive pool of vesicles contributes to linearity at the rod photoreceptor ribbon synapse
AU - Thoreson, Wallace B.
AU - Rabl, Katalin
AU - Townes-Anderson, Ellen
AU - Heidelberger, Ruth
N1 - Funding Information:
This study was supported by NEI grants EY-10542, EY-12128, EY-12031, and EY-10608, Research to Prevent Blindness, Gifford Foundation, Coalition for Brain Injury Research, and the Esther and Joseph Klingenstein Fund. We thank Gary Matthews and Paul Witkovsky for suggestions to the manuscript.
PY - 2004/5/27
Y1 - 2004/5/27
N2 - Studies of the properties of synaptic transmission have been carried out at only a few synapses. We analyzed exocytosis from rod photoreceptors with a combination of physiological and ultrastructural techniques. As at other ribbon synapses, we found that rods exhibited rapid kinetics of release, and the number of vesicles in the releasable pool is comparable to the number of vesicles tethered at ribbon-style active zones. However, unlike other previously studied neurons, we identified a highly Ca2+-sensitive pool of releasable vesicles with a relatively shallow relationship between the rate of exocytosis and [Ca2+]i that is nearly linear over a presumed physiological range of intraterminal [Ca2+]. The low-order [Ca 2+] dependence of release promotes a linear relationship between Ca2+ entry and exocytosis that permits rods to relay information about small changes in illumination with high fidelity at the first synapse in vision.
AB - Studies of the properties of synaptic transmission have been carried out at only a few synapses. We analyzed exocytosis from rod photoreceptors with a combination of physiological and ultrastructural techniques. As at other ribbon synapses, we found that rods exhibited rapid kinetics of release, and the number of vesicles in the releasable pool is comparable to the number of vesicles tethered at ribbon-style active zones. However, unlike other previously studied neurons, we identified a highly Ca2+-sensitive pool of releasable vesicles with a relatively shallow relationship between the rate of exocytosis and [Ca2+]i that is nearly linear over a presumed physiological range of intraterminal [Ca2+]. The low-order [Ca 2+] dependence of release promotes a linear relationship between Ca2+ entry and exocytosis that permits rods to relay information about small changes in illumination with high fidelity at the first synapse in vision.
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U2 - 10.1016/S0896-6273(04)00254-5
DO - 10.1016/S0896-6273(04)00254-5
M3 - Article
C2 - 15157421
AN - SCOPUS:2442458750
SN - 0896-6273
VL - 42
SP - 595
EP - 605
JO - Neuron
JF - Neuron
IS - 4
ER -