TY - JOUR
T1 - Synaptic Vesicle Exocytosis at the Dendritic Lobules of an Inhibitory Interneuron in the Mammalian Retina
AU - Balakrishnan, Veeramuthu
AU - Puthussery, Theresa
AU - Kim, Mean Hwan
AU - Taylor, W. Rowland
AU - Von Gersdorff, Henrique
N1 - Publisher Copyright:
© 2015 Elsevier Inc.
PY - 2015/8/5
Y1 - 2015/8/5
N2 - Ribbon synapses convey sustained and phasic excitatory drive within retinal microcircuits. However, the properties of retinal inhibitory synapses are less well known. AII-amacrine cells are interneurons in the retina that exhibit large glycinergic synapses at their dendritic lobular appendages. Using membrane capacitance measurements, we observe robust exocytosis elicited by the opening of L-type Ca2+ channels located on the lobular appendages. Two pools of synaptic vesicles were detected: a small, rapidly releasable pool and a larger and more slowly releasable pool. Depending on the stimulus, either paired-pulse depression or facilitation could be elicited. During early postnatal maturation, the coupling of the exocytosis Ca2+-sensor to Ca2+ channel becomes tighter. Light-evoked depolarizations of the AII-amacrine cell elicited exocytosis that was graded to light intensity. Our results suggest that AII-amacrine cell synapses are capable of providing both phasic and sustained inhibitory input to their postsynaptic partners without the benefit of synaptic ribbons.
AB - Ribbon synapses convey sustained and phasic excitatory drive within retinal microcircuits. However, the properties of retinal inhibitory synapses are less well known. AII-amacrine cells are interneurons in the retina that exhibit large glycinergic synapses at their dendritic lobular appendages. Using membrane capacitance measurements, we observe robust exocytosis elicited by the opening of L-type Ca2+ channels located on the lobular appendages. Two pools of synaptic vesicles were detected: a small, rapidly releasable pool and a larger and more slowly releasable pool. Depending on the stimulus, either paired-pulse depression or facilitation could be elicited. During early postnatal maturation, the coupling of the exocytosis Ca2+-sensor to Ca2+ channel becomes tighter. Light-evoked depolarizations of the AII-amacrine cell elicited exocytosis that was graded to light intensity. Our results suggest that AII-amacrine cell synapses are capable of providing both phasic and sustained inhibitory input to their postsynaptic partners without the benefit of synaptic ribbons.
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U2 - 10.1016/j.neuron.2015.07.016
DO - 10.1016/j.neuron.2015.07.016
M3 - Article
C2 - 26247863
AN - SCOPUS:84938589680
SN - 0896-6273
VL - 87
SP - 563
EP - 575
JO - Neuron
JF - Neuron
IS - 3
ER -