title: Proopiomelanocortin and melanocortin receptors in the adult rat retino-tectal system and their regulation after optic nerve transection.
abstract: The aim of this study was to characterise the expression of the melanocortin system in the normal and injured rat visual system. Using real-time polymerase chain reaction and immunohistochemistry, we detected melanocortin MC(3), MC(4) and MC(5) receptors and proopiomelanocortin in adult retina and superior colliculus. Melanocortin MC(4) receptor mRNA was the most abundant receptor. Melanocortin MC(3), MC(4) and MC(5) receptors were localised to the ganglion cell and inner nuclear layers and the melanocortin MC(3) and MC(4) receptors were localised to retinal ganglion cells. Transection of the optic nerve leads to ganglion cell death and both melanocortin receptor and proopiomelanocortin expression decreased in superior colliculus after transection whereas the expression was unchanged or even increased in the retina. alpha-Melanocyte-stimulating hormone elicited neurite outgrowth from embryonic retinal explants. Together, these data implicate a role for the melanocortin system in the adult rat retina and that melanocortins can stimulate neurite growth from retinal neurons.
authors.affiliation: Unit for Developmental Neuroscience, Department of Neuroscience, Biomedical Center, Uppsala University, Box 587, S-75123 Uppsala, Sweden.
authors.forename: Niclas
authors.initials: N
authors.lastname: Lindqvist
authors.forename: Ulla
authors.initials: U
authors.lastname: Näpänkangas
authors.forename: Jonas
authors.initials: J
authors.lastname: Lindblom
authors.forename: Finn
authors.initials: F
authors.lastname: Hallböök
mesh_terms: D000818:Animals; D002642:Chick Embryo; D005260:Female; D020221:Optic Nerve Injuries / Q000235:genetics / Q000378:metabolism*; D011333:Pro-Opiomelanocortin / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D044104:Receptor, Melanocortin, Type 3 / Q000096:biosynthesis / Q000235:genetics; D044105:Receptor, Melanocortin, Type 4 / Q000096:biosynthesis / Q000235:genetics; D018043:Receptors, Corticotropin / Q000235:genetics / Q000378:metabolism; D044101:Receptors, Melanocortin / Q000096:biosynthesis* / Q000235:genetics; D012160:Retina / Q000378:metabolism*; D013477:Superior Colliculi / Q000378:metabolism*
chemical_list: D012333:RNA, Messenger; D044104:Receptor, Melanocortin, Type 3; D044105:Receptor, Melanocortin, Type 4; D018043:Receptors, Corticotropin; D044101:Receptors, Melanocortin; C086971:melanocortin 5 receptor; D011333:Pro-Opiomelanocortin