{"title":"A subtype of adenosine receptors mediating pigment dispersion in leucophores of the medaka: evidence for an A2-receptor.","authors":"S Namoto","doi":"","DOIUrl":null,"url":null,"abstract":"<p><p>1. Adenosine and its derivatives induced dispersion of leucosomes in leucophores of the medaka, Oryzias latipes. 2. Among the purines used, 5'-N-ethylcarboxiamideadenosine was the most effective and its potency was far greater than that of adenosine, N6-L-phenylisopropyladenosine and N6-cyclohexyladenosine. 3. Methylxanthines inhibited the purine action competitively, but beta adrenergic antagonists and dipyridamole did not. 4. Beta adrenergic agonists and forskolin synergistically augmented the purine action, while Li+ blocked it competitively. 5. The results suggest that medaka leucophores possess A2 adenosine receptors on the cell membranes, the stimulation of which induces leucosome-dispersion response by increasing the cellular level of cyclic AMP through activation of adenylate cyclase activity.</p>","PeriodicalId":10579,"journal":{"name":"Comparative biochemistry and physiology. C, Comparative pharmacology and toxicology","volume":"88 1","pages":"75-81"},"PeriodicalIF":0.0000,"publicationDate":"1987-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Comparative biochemistry and physiology. C, Comparative pharmacology and toxicology","FirstCategoryId":"1085","ListUrlMain":"","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
1. Adenosine and its derivatives induced dispersion of leucosomes in leucophores of the medaka, Oryzias latipes. 2. Among the purines used, 5'-N-ethylcarboxiamideadenosine was the most effective and its potency was far greater than that of adenosine, N6-L-phenylisopropyladenosine and N6-cyclohexyladenosine. 3. Methylxanthines inhibited the purine action competitively, but beta adrenergic antagonists and dipyridamole did not. 4. Beta adrenergic agonists and forskolin synergistically augmented the purine action, while Li+ blocked it competitively. 5. The results suggest that medaka leucophores possess A2 adenosine receptors on the cell membranes, the stimulation of which induces leucosome-dispersion response by increasing the cellular level of cyclic AMP through activation of adenylate cyclase activity.