title: Expression of melanopsin during development of the rat retina.
abstract: There is accumulating evidence that the new opsin-like protein, melanopsin, in adult rodents functions as non-visual photoreceptor. Here we report using immunohistochemistry and in situ hybridisation that melanopsin during rat retinal development is expressed already at prenatal day 18 in cells of the inner neuroblast layer. Perinatally the melanopsin positive cells increase in number and migrate towards the ganglion cell layer. During early postnatal development a melanopsin immunoreactive dendritic network is formed in the inner plexiform layer. Melanopsin is exclusively expressed in PACAP-containing cells which in adults become the retinal ganglion cells constituting the retinohypothalamic tract. The early expression of melanopsin argues for a photoreceptor role in the developing retinohypothalamic tract which is functional as early as the first day after birth.
authors.affiliation: Department of Clinical Biochemistry, Bispebjerg Hospital, DK-2400 Copenhagen NV, Denmark. bbhjanf@inet.uni2.dk
authors.forename: Jan
authors.initials: J
authors.lastname: Fahrenkrug
authors.forename: Henriette S
authors.initials: HS
authors.lastname: Nielsen
authors.forename: Jens
authors.initials: J
authors.lastname: Hannibal
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D004622:Embryo, Mammalian; D005260:Female; D018507:Gene Expression Regulation, Developmental; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D009479:Neuropeptides / Q000378:metabolism; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051381:Rats; D017208:Rats, Wistar; D012160:Retina / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D017299:Rod Opsins / Q000378:metabolism*; D000099210:Melanopsin
chemical_list: D009479:Neuropeptides; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D017299:Rod Opsins; D000099210:Melanopsin; C495403:Adcyap1 protein, rat