Immunohistochemical and morphological characterization of GABAergic cells in LEC

Abstract

The two subdivisions of the entorhinal cortex, the medial and the lateral entorhinal cortex have been implicated a crucial role in spatial cognition but appear to be functionally distinct. To understand the functional contribution of the lateral entorhinal cortex basic knowledge about the neurons constituting the system is needed. In this study, the GABAergic cell population in LEC was immunohistochemically and morphologically characterized. For this purpose, the transgenic mouse line GAD 67 – GFP was used for immunohistochemical investigation of co-localization of GABA with Ca2+ binding proteins and neuropeptides. A morphological study of GAD positive cells in L II / III of LEC was additionally performed by intracellular injections of Alexa Fluor Hydrazide 568 in fixed brain slices. The results indicate that the GABAergic cell population in LEC is neurochemically and morphologically diverse. The pattern of distribution across LEC for all immunoreactive cell groups, suggests that a diverse cell population is present across all areas of LEC but display a speficic pattern of distribution across LEC laminae.