beta-Endorphin expression in the mouse retina.
Evidence showing expression of endogenous opioids in the mammalian retina is sparse. In the present study we examined a transgenic mouse line expressing an obligate dimerized form of Discosoma red fluorescent protein (DsRed) under the control of the pro-opiomelanocortin promoter and distal upstream regulatory elements to assess whether pro-opiomelanocortin peptide (POMC), and its opioid cleavage product, beta-endorphin, are expressed in the mouse retina. Using double label immunohistochemistry we found that DsRed fluorescence was restricted to a subset of GAD-67-positive cholinergic amacrine cells of both orthotopic and displaced subtypes. About 50% of cholinergic amacrine cells colocalized DsRed and a large fraction of DsRed-expressing amacrine cells was positive for beta-endorphin immunostaining, whereas beta-endorphin-immunoreactive neurons were absent in retinas of POMC null mice. Our findings contribute to a growing body of evidence demonstrating that opioid peptides are an integral component of vertebrate retinas, including those of mammals.
Gallagher
Shannon K
SK
Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA.
Witkovsky
Paul
P
Roux
Michel J
MJ
Low
Malcolm J
MJ
Otero-Corchon
Veronica
V
Hentges
Shane T
ST
Vigh
Jozsef
J
D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D025042:Amacrine Cells / Q000378:metabolism; D000818:Animals; D000918:Antibody Specificity; D064032:Calbindin 2; D064026:Calbindins; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D005968:Glutamate Decarboxylase / Q000378:metabolism; D050487:Glycine Plasma Membrane Transport Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D008164:Luminescent Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D018613:Microscopy, Confocal; D010275:Parasympathetic Nervous System / Q000378:metabolism; D010902:Pituitary Gland / Q000378:metabolism; D011333:Pro-Opiomelanocortin / Q000096:biosynthesis / Q000235:genetics; D012160:Retina / Q000378:metabolism*; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D000521:alpha-MSH / Q000378:metabolism; D001615:beta-Endorphin / Q000096:biosynthesis*; D000097573:Red Fluorescent Protein
D000324:Adrenocorticotropic Hormone; D064032:Calbindin 2; D064026:Calbindins; D002795:Choline O-Acetyltransferase; D005968:Glutamate Decarboxylase; D050487:Glycine Plasma Membrane Transport Proteins; D008164:Luminescent Proteins; D011333:Pro-Opiomelanocortin; D064030:S100 Calcium Binding Protein G; D000521:alpha-MSH; D001615:beta-Endorphin; D000097573:Red Fluorescent Protein; C493267:Slc6a9 protein, mouse