title: Spatial and temporal distribution patterns of enkephalinergic neurons in adult and developing retinas of the preproenkephalin-green fluorescent protein transgenic mouse.
abstract: Enkephalin (ENK) peptides are present in the retina of several vertebrate species and play a crucial role in establishing specific circuits during retinal development. However, there is no information available concerning the development of ENKergic neurons in the mouse retina. To address this question, we used preproenkephalin-enhanced green fluorescent protein (GFP) transgenic mice, in which ENKergic neurons are revealed by GFP. Our results showed that most GFP-positive cells were located in the proximal part of the inner nuclear layer with a scattering of GFP-immunoreactive cells in the ganglion cell layer (GCL) in the adult retina. Double immunostaining with syntaxin indicates that GFP expression was restricted to a population of amacrine cells. The proportions of glycine transporter-1 and γ-aminobutyric acid-positive cells among ENKergic neurons were 57.3 ± 2.4% and 10.1 ± 1.8%, respectively. We then injected retrograde tracer into the superior colliculus and observed that none of the ENKergic neurons in the GCL were retrogradely labeled with the tracer. GFP-positive cells were first observed at embryonic day (E) 15 in the inner neuroblastic layer at only very low levels, which gradually increased until E18. After birth, there was a steep rise in GFP expression levels, reaching maximal activity by postnatal day (P) 7. The distribution and intensity of GFP-positive cells at P15 were similar to those of adult retina. It was found that immunoreactive processes in the inner plexiform layer formed strongly stained patches. The present results provide detailed morphological evidence of the cell type and spatial and temporal distribution of ENKergic neurons in the retina.
authors: Department of Anatomy, Histology and Embryology, K.K. Leung Brain Research Centre, Fourth Military Medical University, Xi'an, PR China.
authors: Jing
authors: J
authors: Huang
authors: Yan
authors: Y
authors: Lin
authors: Rui
authors: R
authors: Han
authors: Jing
authors: J
authors: Chen
authors: Ya-Yun
authors: YY
authors: Wang
authors: Wen
authors: W
authors: Wang
authors: Yan-Yan
authors: YY
authors: Wei
authors: Takeshi
authors: T
authors: Kaneko
authors: Yun-Qing
authors: YQ
authors: Li
authors: Sheng-Xi
authors: SX
authors: Wu
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D004745:Enkephalins / Q000378:metabolism*; D050487:Glycine Plasma Membrane Transport Proteins / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D009474:Neurons / Q000166:cytology* / Q000378:metabolism*; D010751:Phosphopyruvate Hydratase / Q000378:metabolism; D011498:Protein Precursors / Q000378:metabolism*; D050765:Qa-SNARE Proteins / Q000378:metabolism; D012160:Retina / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D013266:Stilbamidines / Q000378:metabolism; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D004745:Enkephalins; D050487:Glycine Plasma Membrane Transport Proteins; D011498:Protein Precursors; D050765:Qa-SNARE Proteins; D013266:Stilbamidines; D049452:Green Fluorescent Proteins; D005680:gamma-Aminobutyric Acid; C033660:preproenkephalin; D010751:Phosphopyruvate Hydratase