Linked Life Data

1678012

Source:http://linkedlifedata.com/resource/pubmed/id/1678012

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1991-9-11
pubmed:abstractText
Pigment aggregation in melanophores from the cuckoo wrasse (Labrus ossifagus L.) has previously been shown to be mediated by alpha-2 adrenoceptors. In the present investigation, the effect of amiloride on pigment aggregation induced by noradrenaline and B-HT 920 was studied. Amiloride caused a parallel shift to the right in concentration-response curves for 5-allyl-2-amino-5,6,7,8-tetrahydrothiazolo-[4,5-d]azepine-dihyd roc hloride: (B-HT 920), with no change in the maximal response, indicating simple competitive inhibition. Subsequent Schild plot analysis gave a straight line with a slope of almost unity (0.95) and a KB of 5 x 10(-6) M. In contrast to the effect of amiloride on B-HT 920-induced pigment aggregation, only a very high concentration of amiloride (1 x 10(3) M) inhibited the corresponding effect of noradrenaline. Na+/H+ exchange has been suggested as a possible mechanism for alpha-2 adrenoceptors, and the amiloride analogs 5-(N,N-dimethyl)amiloride and 5-(N,N-hexamethylene)amiloride are known to be more specific than amiloride itself in this respect. However, these analogs inhibited the effect of B-HT 920 significantly less effectively than amiloride. Furthermore, manipulating the extracellular pH between 6.8 and 7.8 did not affect the concentration response curves of B-HT 920. Neither did the prostanoid pathway inhibitors, quinacrine or indomethacin, inhibit the pigment-aggregating effect of B-HT 920. The present results suggest that amiloride competes with B-HT 920 as receptor antagonist, and that Na+/H+ exchange is insignificant for the alpha-2 adrenoceptor-stimulated pigment aggregation.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0022-3565
pubmed:author
pubmed:issnType
Print
pubmed:volume
258
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
447-51
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Antagonistic effect of amiloride on alpha-2 adrenoceptor-mediated pigment aggregation: pharmacological heterogeneity between B-HT 920 and noradrenaline.
pubmed:affiliation
Department of Pharmacology, Linköping University, Sweden.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't