Linked Life Data

16186625

Source:http://linkedlifedata.com/resource/pubmed/id/16186625

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2005-9-27
pubmed:abstractText
Circadian rhythms are daily adjusted to the environmental day/night cycle by photic input via the retinohypothalamic tract (RHT). Recent studies indicate that melanopsin, a newly identified opsin-like molecule, is involved in the light responsiveness of retinal ganglion cells (RGCs) constituting the RHT. In the present study, we examined the expression of melanopsin at the mRNA and protein level during a day/night cycle and during prolonged periods of light and darkness in the retina of albino Wistar rats. We observed a diurnal change in melanopsin, with mRNA level being highest at early subjective night and protein level highest at late subjective day. Prolonged exposure to darkness significantly increased melanopsin mRNA level as early as the first day, and the expression continued to increase during 5 d in darkness. The decrease in mRNA level during exposure to constant light was slower. After 48 h of light, the melanopsin mRNA level was significantly reduced, and an almost undetectable level was found after 5 d. The induction of melanopsin by darkness was even more pronounced if darkness was preceded by light suppression for 5 d. By use of immunohistochemistry, we showed that darkness increased the amount of protein in the dendritic processes, resulting in a dense network covering the entire retina. Constant light decreased melanopsin immunostaining time dependently, beginning in the distal dendrites and progressing to the proximal dendrites and the soma. Our observations suggest that the intrinsic light-responsive RGCs adapt their expression of the putative circadian photopigment melanopsin to environmental light and darkness.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:issn
0895-8696
pubmed:author
pubmed:issnType
Print
pubmed:volume
27
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
147-55
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Light and darkness regulate melanopsin in the retinal ganglion cells of the albino Wistar rat.
pubmed:affiliation
Department of Clinical Biochemistry, Bispebjerg Hospital, University of Copenhagen, DK-2400 Copenhagen NV, Denmark. J.Hannibal@inet.uni2.dk
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't