TY - JOUR
T1 - Mechanism of High-Frequency Signaling at a Depressing Ribbon Synapse
AU - Grabner, Chad P.
AU - Ratliff, Charles P.
AU - Light, Adam C.
AU - DeVries, Steven H.
N1 - Funding Information:
This work was supported by NIH grant EY012141 (S.H.D.) and Research to Prevent Blindness.
PY - 2016/7/6
Y1 - 2016/7/6
N2 - Ribbon synapses mediate continuous release in neurons that have graded voltage responses. While mammalian retinas can signal visual flicker at 80–100 Hz, the time constant, τ, for the refilling of a depleted vesicle release pool at cone photoreceptor ribbons is 0.7–1.1 s. Due to this prolonged depression, the mechanism for encoding high temporal frequencies is unclear. To determine the mechanism of high-frequency signaling, we focused on an “Off” cone bipolar cell type in the ground squirrel, the cb2, whose transient postsynaptic responses recovered following presynaptic depletion with a τ of ∼0.1 s, or 7- to 10-fold faster than the τ for presynaptic pool refilling. The difference in recovery time course is caused by AMPA receptor saturation, where partial refilling of the presynaptic pool is sufficient for a full postsynaptic response. By limiting the dynamic range of the synapse, receptor saturation counteracts ribbon depression to produce rapid recovery and facilitate high-frequency signaling.
AB - Ribbon synapses mediate continuous release in neurons that have graded voltage responses. While mammalian retinas can signal visual flicker at 80–100 Hz, the time constant, τ, for the refilling of a depleted vesicle release pool at cone photoreceptor ribbons is 0.7–1.1 s. Due to this prolonged depression, the mechanism for encoding high temporal frequencies is unclear. To determine the mechanism of high-frequency signaling, we focused on an “Off” cone bipolar cell type in the ground squirrel, the cb2, whose transient postsynaptic responses recovered following presynaptic depletion with a τ of ∼0.1 s, or 7- to 10-fold faster than the τ for presynaptic pool refilling. The difference in recovery time course is caused by AMPA receptor saturation, where partial refilling of the presynaptic pool is sufficient for a full postsynaptic response. By limiting the dynamic range of the synapse, receptor saturation counteracts ribbon depression to produce rapid recovery and facilitate high-frequency signaling.
UR - http://www.scopus.com/inward/record.url?scp=84991244321&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84991244321&partnerID=8YFLogxK
U2 - 10.1016/j.neuron.2016.05.019
DO - 10.1016/j.neuron.2016.05.019
M3 - Article
C2 - 27292536
AN - SCOPUS:84991244321
VL - 91
SP - 133
EP - 145
JO - Neuron
JF - Neuron
SN - 0896-6273
IS - 1
ER -