Coexistence of GAD-65 and GAD-67 with tyrosine hydroxylase and nitric oxide synthase in amacrine and interplexiform cells of the primate, Cebus apella

Abstract

The expression of glutamate decarboxylase forms, GAD-65 and GAD-67, in GABAergic cells was studied by immunocytochemistry in the retina of the New World monkey, Cebus apella. In the innermost rows of the inner nuclear layer (INL), somata that express GABA correspond to about 45% of the total number of cells in the central retina and about 25% on the periphery. Three subsets of GABAergic amacrine cells were identified along the horizontal meridian: about 5% express only GAD-65 and 40% GAD-67, and approximately 50% contain both forms of GAD. In the INL, GAD-65 immunoreactivity was detected in broad bands around strata 1, 3, and 5. GAD-67 immunoreactivity was observed throughout all strata. Somata that expressed GAD-67 exclusively stratified only in narrow bands around strata 2 and 4 of the INL and colocalized with beta2 and beta3 subunits of GABA-A receptor. Interplexiform and amacrine cells that express GABA also express tyrosine hydroxylase (TH) or nitric oxide synthase (NOS). GAD-67 colocalized with TH or NOS in presumed amacrine cells of the inner plexiform layer (IPL) and ganglion cell layer (GCL). GAD-65 was expressed in the TH- and NOS-immunoreactive interplexiform and amacrine cells, respectively. Different from what has been described in other mammals, TH and NOS were coexpressed in some neurons, indicating a partial overlap in retinal cell populations containing dopamine or nitric oxide in this primate.

Quantification and characterization of GABA‐ergic amacrine cells in the retina of GAD67‐GFP knock‐in mice

“…By contrast with the reported co‐localization of TH and GABA in the monkey, cat and mouse (Wässle & Chun 1988; Haverkamp & Wässle 2000; Andrade da Costa & Hoko 2003), there was no co‐localization between TH and GFP in our study. This might reflect the fact that the GFP in our mouse model was related to GAD67.…”

“…1998; Haverkamp et al. 2000; Andrade da Costa & Hoko 2003). We were able to confirm this finding in the mouse.…”

Immunocytochemical Evidence of the Localization of the Crumbs Homologue 3 Protein (CRB3) in the Developing and Mature Mouse Retina

“…GAD65 and 67 are the two isoforms of the enzyme glutamate decarboxylase, which catalyzes the decarboxylation of glutamate to GABA in the retina [32], [48], [49]. It has been reported that in mammalian retinas, the GABAergic amacrine cells can express either or both GAD isoforms [49], [50]. Using an antibody that recognizes both GAD isoforms, we have shown in the present work that CRB3 colocalizes with most GAD65/67 processes.…”

Morphology and Immunoreactivity of Retrogradely Double-Labeled Ganglion Cells in the Mouse Retina

“…This result confirms that bNOS, ChAT, GAD, and glycine are reliable AC markers in the GCL. We also observed that bNOS-IR was mostly colocalized with GABA-IR, which is in line with previous studies [51][52][53] In contrast, GCs and ACs were both found to accumulate 5-HT, and these cells resided in either the GCL or INL. Thus, GCs and ACs cannot be distinguished by observation of 5-HT accumulation.…”