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.
Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA.
Shannon K
SK
Gallagher
Paul
P
Witkovsky
Michel J
MJ
Roux
Malcolm J
MJ
Low
Veronica
V
Otero-Corchon
Shane T
ST
Hentges
Jozsef
J
Vigh
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