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GE-25-like immunoreactivity in the rat eye
Journal article   Peer reviewed

GE-25-like immunoreactivity in the rat eye

Katrin Lorenz, Oliver W Gramlich, Franz H Grus, Daniela Ehrlich, Christian Humpel, Marina Nogalo, Reiner Fischer-Colbrie, Nikolaos E Bechrakis, Rosa Hattmannstorfer and Josef Troger
Peptides (New York, N.Y. : 1980), Vol.36(2), pp.286-291
08/2012
DOI: 10.1016/j.peptides.2012.04.022
PMID: 22634234

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Abstract

► GE-25 is a neuropeptide generated in vivo by proteolytic processing of chromogranin A. ► In the retina and trigeminal ganglion GE-25-like immunoreactivity appeared as uncleaved intact chromogranin A. ► GE-25-like immunoreactivity was found to be distinctly distributed throughout the rat eye. ► The peptide has been localized to small and medium-sized ganglion cells in the rat trigeminal ganglion. ► In the retina, immunoreactivity has been localized to glia which is atypical for neuropeptides. This study aimed to investigate the presence and distribution of the chromogranin A-derived peptide GE-25 in the rat eye. The molecular form detected by the GE-25 antiserum was evaluated in the rat trigeminal ganglion, retina and remaining tissues of the rat eye by means of Western blots and the distribution pattern of GE-25-like immunoreactivity was studied in the rat eye and rat trigeminal ganglion by immunofluorescence. One single band of approximately 70kDa was stained in the trigeminal ganglion and retina which represents the uncleaved intact chromogranin A indicating that the proteolytic processing of chromogranin A to GE-25 is limited in these tissues. Sparse GE-25-like immunoreactive nerve fibers were visualized in the corneal stroma, at the limbus around blood vessels, in the sphincter and dilator muscle and stroma of the iris, in the stroma of the ciliary body and ciliary processes and in the stroma and around blood vessels in the choroid. This distribution pattern is characteristic for neuropeptides whereas the presence of immunoreactivity in the corneal endothelium and in Müller glia in the retina is atypical. GE-25-like immunoreactivity was found in small to medium-sized ganglion cells in the rat trigeminal ganglion clearly indicating that the nerve fibers in the rat eye are of sensory origin. The colocalization of GE-25-immunoreactivity with SP-immunoreactivity in the rat ciliary body is in agreement with the presumption of the sensory nature of the innervation of the anterior segment of the eye by GE-25.
Eye Retina GE-25 Trigeminal ganglion

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