Linked Life Data

8752113

Source:http://linkedlifedata.com/resource/pubmed/id/8752113

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1996-10-2
pubmed:abstractText
Nitric oxide plays an important role as an intercellular messenger in the CNS. In the present work we measured NADPH-diaphorase activity, which is considered to be a marker of cells producing nitric oxide, in homogenates of the developing chick retina. The enzyme activity can be detected beginning in 8-day-old embryonic retinas with no further quantitative variations throughout development. Arginine analogues inhibit approximately 65% of the activity in embryonic retinas and 50% in posthatched retinas. The enzyme is stimulated 50% by 2 mM calcium chloride in retinas from 8 to 14 embryonic days, but this effect decreases to 20% in 17-day embryonic retinas and practically disappears in posthatched animals. The stimulation by calcium is completely blocked by arginine analogues. The decrease in enzyme activity at posthatched retinas is not due to stimulation by endogenous calcium or the presence of insufficient amounts of calmodulin, because addition of EGTA or calmodulin, respectively, did not restore the stimulation to levels observed at embryonic stages. Inhibition of NADPH-diaphorase activity by NG-nitro-L-arginine or L-NG-(iminoethyl) ornithine is concentration dependent with IC50 values of approximately 1 mM at all stages studied. However, in the presence of calcium, the inhibition by both analogues is shifted to the left and is apparently biphasic at all developmental stages, including in posthatched animals, with IC50 values in the low micromolar range. NADPH-diaphorase was also detected by histochemistry in specific groups of cells in the early embryonic retina and in subsets of amacrine and ganglion cells, as well as in photoreceptors, in more developed retinas. The results indicate that different isoforms of nitric oxide synthase are present in the chick retina and that a calcium-dependent isoform is predominant in early periods of development.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0022-3042
pubmed:author
pubmed:issnType
Print
pubmed:volume
67
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1063-71
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Development of NADPH-diaphorase in the avian retina: regulation by calcium ions and relation to nitric oxide synthase.
pubmed:affiliation
Department of Neurobiology, Federal Fluminense University, Rio de Janeiro, Brazil.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't