title: Identification and characterization of an aquaporin 1 immunoreactive amacrine-type cell of the mouse retina.
abstract: Using immunocytochemistry, a type of amacrine cell that is immunoreactive for aquaporin 1 was identified in the mouse retina. AQP1 immunoreactivity was found in photoreceptor cells of the outer nuclear layer (ONL) and in a distinct type of amacrine cells of the inner nuclear layer (INL). AQP1-immunoreactive (IR) amacrine cell somata were located in the INL and their processes extended through strata 3 and 4 of the inner plexiform layer (IPL) with thin varicosities. The density of the AQP1-IR amacrine cells increased from 100/mm(2) in the peripheral retina to 350/mm(2) in the central retina. The AQP1-IR amacrine cells comprise 0.5% of the total amacrine cells. The AQP1-IR amacrine cell bodies formed a regular mosaic, which suggested that they represent a single type of amacrine cell. Double labeling with AQP1 and glycine, gamma-aminobutyric acid (GABA) or GAD(65) antiserum demonstrated that the AQP1-IR amacrine cells expressed GABA or GAD(65) but not glycine. Their synaptic input was primarily from other amacrine cell processes. They also received synaptic inputs from a few cone bipolar cells. The primary synaptic targets were ganglion cells, followed by other amacrine cells and cone bipolar cells. In addition, gap junctions between an AQP1-IR amacrine process and another amacrine process were rarely observed. In summary, a GABAergic amacrine cell type labeled by an antibody against AQP1 was identified in the mouse retina and was found to play a possible role in transferring a certain type of visual information from other amacrine or a few cone bipolar cells primarily to ganglion cells.
authors.affiliation: Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea.
authors.forename: Tae-Hoon
authors.initials: TH
authors.lastname: Kang
authors.forename: Yeon-Kyung
authors.initials: YK
authors.lastname: Choi
authors.forename: In-Beom
authors.initials: IB
authors.lastname: Kim
authors.forename: Su-Ja
authors.initials: SJ
authors.lastname: Oh
authors.forename: Myung-Hoon
authors.initials: MH
authors.lastname: Chun
mesh_terms: D025042:Amacrine Cells / Q000378:metabolism* / Q000648:ultrastructure; D026922:Amino Acid Transport Systems, Acidic / Q000378:metabolism; D000818:Animals; D051398:Aquaporin 1; D020346:Aquaporins / Q000302:isolation & purification* / Q000378:metabolism; D015153:Blotting, Western / Q000379:methods; D002452:Cell Count / Q000379:methods; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D007150:Immunohistochemistry / Q000379:methods; D007527:Isoenzymes / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018613:Microscopy, Confocal / Q000379:methods; D016253:Microscopy, Immunoelectron / Q000379:methods; D012160:Retina / Q000166:cytology* / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D026922:Amino Acid Transport Systems, Acidic; D051398:Aquaporin 1; D020346:Aquaporins; D002795:Choline O-Acetyltransferase; D005968:Glutamate Decarboxylase; D005998:Glycine; D007527:Isoenzymes; D033921:Vesicular Transport Proteins; D005680:gamma-Aminobutyric Acid; C496021:Aqp1 protein, mouse; C504941:Slc17a8 protein, mouse; C401141:glutamate decarboxylase 2