Developmental expression pattern of phototransduction components in mammalian pineal implies a light-sensing function.
Whereas the pineal organs of lower vertebrates have been shown to be photosensitive, photic regulation of pineal function in adult mammals is thought be mediated entirely by retinal photoreceptors. Extraretinal regulation of pineal function has been reported in neonatal rodents, although both the site and molecular basis of extraretinal photoreception have remained obscure. In this study we examine the developmental expression pattern of all of the principal components of retinal phototransduction in rat pineal via cRNA in situ hybridization. All of the components needed to reconstitute a functional phototransduction pathway are expressed in the majority of neonatal pinealocytes, although the expression levels of many of these genes decline dramatically during development. These findings strongly support the theory that the neonatal rat pineal itself is photosensitive. In addition, we observe in neonatal pinealocytes the expression of both rod-specific and cone-specific phototransduction components, implying the existence of functionally different subtypes of pinealocytes that express varying combinations of phototransduction enzymes.
Blackshaw
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Johns Hopkins University School of Medicine, Department of Neuroscience, Baltimore, Maryland 21205, USA.
Snyder
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SH
D000818:Animals; D000831:Animals, Newborn; D019393:Arrestin / Q000096:biosynthesis / Q000235:genetics; D002135:Calcium-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D005136:Eye Proteins / Q000096:biosynthesis / Q000235:genetics; D051606:G-Protein-Coupled Receptor Kinase 1; D018507:Gene Expression Regulation, Developmental / Q000528:radiation effects; D051597:Hippocalcin; D017403:In Situ Hybridization; D015640:Ion Channel Gating; D008027:Light; D008074:Lipoproteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics; D009928:Organ Specificity; D010727:Phosphoric Diester Hydrolases / Q000096:biosynthesis / Q000235:genetics; D010870:Pineal Gland / Q000166:cytology / Q000254:growth & development / Q000378:metabolism / Q000528:radiation effects*; D011494:Protein Kinases / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D051603:Recoverin; D012177:Retinol-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D012243:Rhodopsin / Q000096:biosynthesis* / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology / Q000528:radiation effects*; D015293:Transducin / Q000096:biosynthesis* / Q000235:genetics; D000099214:Retinol-Binding Proteins, Interstitial
D019393:Arrestin; D002135:Calcium-Binding Proteins; D005136:Eye Proteins; D051606:G-Protein-Coupled Receptor Kinase 1; D051597:Hippocalcin; D008074:Lipoproteins; D009419:Nerve Tissue Proteins; D010727:Phosphoric Diester Hydrolases; D011494:Protein Kinases; D012333:RNA, Messenger; D051603:Recoverin; D012177:Retinol-Binding Proteins; D012243:Rhodopsin; D015293:Transducin; D000099214:Retinol-Binding Proteins, Interstitial; C496732:Rcvrn protein, mouse; C496733:Rcvrn protein, rat; C496762:Grk1 protein, mouse; C496765:Grk1 protein, rat