Linked Life Data

20148284

Source:http://linkedlifedata.com/resource/pubmed/id/20148284

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2010-5-13
pubmed:abstractText
The light/dark cycle is the most important circadian clock synchronizer for mammals and humans. Circadian rhythms of dopamine and melatonin production in the retina have been reported to follow the light and dark cycle, but their impact on rod and cone functioning is not clear. The purpose of this study was to assess diurnal variations (morning vs. evening) in retinal function as measured with the photopic and scotopic electroretinogram (ERG). We also tried to correlate our results with the presence or absence of melatonin secretion in the saliva. Photopic and scotopic luminance-response functions were obtained in 29 participants at 11:00 (when melatonin should not be present) and 23:00 (when melatonin should be present). From the luminance-response function, Vmax, log K and slope parameters were derived. In scotopic condition, a significant increase of 6% in Vmax amplitude was observed in evening compared to morning (P = 0.03) along with a prolonged b-wave implicit time of 8% (P = 0.01) and an increase in rod sensitivity in evening compared to morning (P = 0.02). As expected, these changes in rod function were accompanied by a higher concentration of melatonin in saliva samples in the evening (P = 0.01). In photopic condition, only a prolonged a-wave implicit time of 5% was observed in evening when compared to morning (P = 0.02). Our findings suggest that the rod system is favored during night time, when circulating melatonin is present. Although statistically significant changes were observed, the day vs. night difference observed in the present study appears to be too small to impact significantly upon clinical assessment of retinal function.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1573-2622
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
120
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
265-72
pubmed:meshHeading
pubmed:year
2010
pubmed:articleTitle
Circadian variation in the electroretinogram and the presence of central melatonin.
pubmed:affiliation
Centre de Recherche Université Laval Robert-Giffard, 2601 de la Canardière, F4500, Québec, QC G1J 2G3, Canada.
pubmed:publicationType
Journal Article