Defining morphologically and genetically distinct GABAergic/cholinergic amacrine cell subtypes in the vertebrate retina

by Yan Li, Shuguang Yu, Xinling Jia, Xiaoying Qiu, Jie He In mammals, retinal direction selectivity originates from GABAergic/cholinergic amacrine cells (ACs) specifically expressing thesox2 gene. However, the cellular diversity of GABAergic/cholinergic ACs of other vertebrate species remains largely unexplored. Here, we identified 2 morphologically and genetically distinct GABAergic/cholinergic AC types in zebrafish, a previously undescribedbhlhe22+ type and a mammalian counterpartsox2+ type. Notably, while solesox2 disruption removedsox2+ type, the codisruption ofbhlhe22 andbhlhe23 was required to removebhlhe22+ type. Also, both types significantly differed in dendritic arbors, lamination, and soma position. Furthermore,in vivo two-photon calcium imaging and the behavior assay suggested the direction selectivity of both AC types. Nevertheless, the 2 types showed preferential responses to moving bars of different sizes. Thus, our findings provide new cellular diversity and functional characteristics of GABAergic/cholinergic ACs in the vertebrate retina.
Source: PLoS Biology: Archived Table of Contents - Category: Biology Authors: Source Type: research