Abstract
Purpose: :
To characterize green fluorescent protein (GFP) expression in the retina of the NPY-GFP transgenic mouse line (B6.FVB-Tg(Npy-hrGFP)1Lowl ) from Jackson Laboratory.
Methods: :
Immunohistochemistry with antibodies to common amacrine and displaced amacrine cell markers, HPC-1, GAT-1, GAD 67 and ChAT, and the nuclear stain DAPI, coupled with confocal microscopy and morphometric techniques, were used to characterize GFP expression in paraformaldehyde fixed transverse retinal sections and wholemounts.
Results: :
NPY-GFP mice were characterized by the extensive expression of GFP in the inner retina, in somata in the ganglion and inner nuclear cell layers (GCL, INL). GFP fluorescent cell bodies and their processes were in all retinal regions and GFP-containing processes ramified in laminae 2-4 of the inner plexiform layer (IPL). GFP fluorescence was not observed in the nerve fiber layer and optic nerve. GFP-containing cell bodies ranged from 6 to 9 µm in diameter and had a density of 859 + 41 cells/mm2 at 1.5 mm from the optic nerve head in the nasal direction in the GCL. 96.2, 89.6, 86.5, and 98.7% of the GFP positive cells in the GCL were HPC-1, GAD 67, GAT-1 and ChAT immunoreactive, respectively. A small percentage of unidentified cells was ChAT negative, had somata in the INL and ramified in lamina 3 of the IPL.
Conclusions: :
These findings show that GFP expression in the NPY-GFP mouse line is localized primarily to the ChAT positive, starburst amacrine cell population. Therefore, the NPY-GFP mouse line is highly useful for identifying cholinergic amacrine cells and their processes in the retina.
Keywords: amacrine cells • transgenics/knock-outs • imaging/image analysis: non-clinical