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Cellular distribution and subcellular localization of molecular components of vesicular transmitter release in horizontal cells of rabbit retina
Author(s) -
Hirano Arlene A.,
Brandstätter Johann H.,
Brecha Nicholas C.
Publication year - 2005
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.20577
Subject(s) - ribbon synapse , biology , synaptic vesicle , microbiology and biotechnology , syntaxin , immunoelectron microscopy , vesicular transport protein , synaptotagmin 1 , axon terminal , neuroscience , vesicle , axon , biochemistry , immunohistochemistry , membrane , immunology
The mechanism underlying transmitter release from retinal horizontal cells is poorly understood. We investigated the possibility of vesicular transmitter release from mammalian horizontal cells by examining the expression of synaptic proteins that participate in vesicular transmitter release at chemical synapses. Using immunocytochemistry, we evaluated the cellular and subcellular distribution of complexin I/II, syntaxin‐1, and synapsin I in rabbit retina. Strong labeling for complexin I/II, proteins that regulate a late step in vesicular transmitter release, was found in both synaptic layers of the retina, and in somata of A‐ and B‐type horizontal cells, of γ‐aminobutyric acid (GABA)‐ and glycinergic amacrine cells, and of ganglion cells. Immunoelectron microscopy demonstrated the presence of complexin I/II in horizontal cell processes postsynaptic to rod and cone ribbon synapses. Syntaxin‐1, a core protein of the soluble N‐ethylmaleimide‐sensitive‐factor attachment protein receptor (SNARE) complex known to bind to complexin, and synapsin I, a synaptic vesicle‐associated protein involved in the Ca 2+ ‐dependent recruitment of synaptic vesicles for transmitter release, were also present in the horizontal cells and their processes at photoreceptor synapses. Photoreceptors and bipolar cells did not express any of these proteins at their axon terminals. The presence of complexin I/II, syntaxin‐1, and synapsin I in rabbit horizontal cell processes and tips suggests that a vesicular mechanism may underlie transmitter release from mammalian horizontal cells. J. Comp. Neurol. 488:70–81, 2005. Published 2005 Wiley‐Liss, Inc.