Linked Life Data

6686468

Source:http://linkedlifedata.com/resource/pubmed/id/6686468

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1-2
pubmed:dateCreated
1984-3-14
pubmed:abstractText
When Richardson's ground squirrels were kept under light:dark cycles of 14:10 h there was no nocturnal rise in pineal hydroxyindole-O-methyltransferase (HIOMT) activity. Conversely, the 10 h dark period was associated with large nocturnal rises in both pineal serotonin-N-acetyltransferase (NAT) activity and radioimmunoassayable melatonin levels. The nighttime rises in pineal NAT and melatonin were not suppressed by the exposure of the animals to a light irradiance of 925 mu W/cm2 during the normal dark period. On the other hand, when the light irradiance was increased to 1850 mu W/cm2 the rise in pineal NAT activity was eliminated while the melatonin rise was greatly reduced. When ground squirrels were acutely exposed to a light irradiance of 1850 mu W/cm2 for 30 min beginning at 5.5 h after lights out, pineal NAT activity and melatonin levels were reduced to daytime values within 30 min. The half-time (t 1/2) for each constituent was less than 10 min. Exposure to a light irradiance of either 5 s or 5 min (beginning at 5.5 h into dark period) was equally as effective as 30 min light exposure in inhibiting pineal NAT activity and melatonin levels. When animals were returned to darkness after a 30 min exposure to a light irradiance of 1850 mu W/cm2 at night, both pineal NAT activity and melatonin levels were restored to high nighttime levels within 2 h of their return to darkness. The results indicate that the pineal gland of the wild-captured, diurnal Richardson's ground squirrel is 9000 X less sensitive to light at night than is the pineal gland of the laboratory raised, nocturnal Syrian hamster.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-8993
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
288
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
151-7
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Influence of light irradiance on hydroxyindole-O-methyltransferase activity, serotonin-N-acetyltransferase activity, and radioimmunoassayable melatonin levels in the pineal gland of the diurnally active Richardson's ground squirrel.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't