Premium
Morphological and physiological properties of enhanced green fluorescent protein ( EGFP )‐expressing wide‐field amacrine cells in the C h AT ‐ EGFP mouse line
Author(s) -
Knop Gabriel C.,
Pottek Mark,
Monyer Hannah,
Weiler Reto,
Dedek Karin
Publication year - 2014
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/ejn.12443
Subject(s) - inner plexiform layer , microbiology and biotechnology , amacrine cell , green fluorescent protein , population , biology , receptive field , cell type , retina , chemistry , cell , neuroscience , biochemistry , demography , sociology , gene
Mammalian retinas comprise a variety of interneurons, among which amacrine cells represent the largest group, with more than 30 different cell types each exhibiting a rather distinctive morphology and carrying out a unique function in retinal processing. However, many amacrine types have not been studied systematically because, in particular, amacrine cells with large dendritic fields, i.e. wide‐field amacrine cells, have a low abundance and are therefore difficult to target. Here, we used a transgenic mouse line expressing the coding sequence of enhanced green fluorescent protein under the promoter for choline acetyltransferase ( C h AT ‐ EGFP mouse) and characterized a single wide‐field amacrine cell population monostratifying in layer 2/3 of the inner plexiform layer ( WA ‐ S 2/3 cell). Somata of WA ‐ S 2/3 cells are located either in the inner nuclear layer or are displaced to the ganglion cell layer and exhibit a low cell density. Using immunohistochemistry, we show that WA ‐ S 2/3 cells are presumably GABA ergic but may also release acetylcholine as their somata are weakly positive for C h AT . Two‐photon‐guided patch‐clamp recordings from intact retinas revealed WA ‐ S 2/3 cells to be ON ‐ OFF cells with a homogenous receptive field even larger than the dendritic field. The large spatial extent of the receptive field is most likely due to the extensive homologous and heterologous coupling among WA ‐ S 2/3 cells and to other amacrine cells, respectively, as indicated by tracer injections. In summary, we have characterized a novel type of GABA ergic ON ‐ OFF wide‐field amacrine cell which is ideally suited to providing long‐range inhibition to ganglion cells due to its strong coupling.