Linked Life Data

15674243

Source:http://linkedlifedata.com/resource/pubmed/id/15674243

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
7027
pubmed:dateCreated
2005-2-17
pubmed:abstractText
Melanopsin has been proposed to be the photopigment of the intrinsically photosensitive retinal ganglion cells (ipRGCs); these photoreceptors of the mammalian eye drive circadian and pupillary adjustments through direct projections to the brain. Their action spectrum (lambda(max) approximately 480 nm) implicates an opsin and melanopsin is the only opsin known to exist in these cells. Melanopsin is required for ipRGC photosensitivity and for behavioural photoresponses that survive disrupted rod and cone function. Heterologously expressed melanopsin apparently binds retinaldehyde and mediates photic activation of G proteins. However, its amino-acid sequence differs from vertebrate photosensory opsins and some have suggested that melanopsin may be a photoisomerase, providing retinoid chromophore to an unidentified opsin. To determine whether melanopsin is a functional sensory photopigment, here we transiently expressed it in HEK293 cells that stably expressed TRPC3 channels. Light triggered a membrane depolarization in these cells and increased intracellular calcium. The light response resembled that of ipRGCs, with almost identical spectral sensitivity (lambda(max) approximately 479 nm). The phototransduction pathway included Gq or a related G protein, phospholipase C and TRPC3 channels. We conclude that mammalian melanopsin is a functional sensory photopigment, that it is the photopigment of ganglion-cell photoreceptors, and that these photoreceptors may use an invertebrate-like phototransduction cascade.
pubmed:commentsCorrections
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
1476-4687
pubmed:author
pubmed:issnType
Electronic
pubmed:day
17
pubmed:volume
433
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
745-9
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
2005
pubmed:articleTitle
Induction of photosensitivity by heterologous expression of melanopsin.
pubmed:affiliation
Department of Neuroscience, Box 1953, Brown University, Providence, Rhode Island 02912-1953, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.