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Article: 2-[125I]Iodomelatonin binding sites in the quail heart: Characteristics, distribution and modulation by guanine nucleotides and cations

Title2-[125I]Iodomelatonin binding sites in the quail heart: Characteristics, distribution and modulation by guanine nucleotides and cations
Authors
KeywordsAutoradiography
Calcium
Guanine nucleotide
Magnesium
Melatonin receptor
Pineal gland
Potassium
Sodium
Issue Date1996
PublisherElsevier Inc. The Journal's web site is located at http://www.elsevier.com/locate/lifescie
Citation
Life Sciences, 1996, v. 58 n. 13, p. 1047-1057 How to Cite?
AbstractTo investigate whether melatonin has a direct action on the cardiovascular system, putative melatonin receptors were studied in quail heart membrane preparations using the specific melatonin agonist 2-[125I]iodomelatonin ([125I]Mel) as the radioligand. The [125I]Mel binding demonstrated in the mature quail heart was saturable, highly specific and reversible, of picomolar affinity and femtomolar density (Kd = 35.2 ±5.2 pM; Bmax = 1.32 ± 0.25 fmol/mg protein; n = 8). The linear Scatchard plots and the close to unity Hill coefficient indicated a single class of binding sites. The pharmacological profile was in the affinity order of 2-iodomelatonin = 2-phenylmelatonin > melatonin > 6-chloromelatonin ⪢ 6-hydroxymelatonin > 6-sulphatoxymelatonin ⪢ N-acetylserotonin ⋙ 5-hydroxytryptamine. Guanosine 5′- riphosphate and guanosine 5'-O-(3-thiotriphosphate) (GTPγS) dose dependently inhibited the binding. Ten μM GTPγS lowered the binding affinity by 50% in saturation studies. The order of potency of inhibition by cations was: Ca2+ > Mg2+ > Li+ > Na+ > K+ > cholinechloride. Contrary to most other melatonin binding sites, millimolar concentrations of Ca2+ and Mg2+ did not promote binding in the quail heart membranes. In vitro autoradiography indicated homogenous labeling in the heart. Our results demonstrated [125I]Mel binding sites in the quail heart. That guanine nucleotides and Na+ inhibited the binding indicated that these putative melatonin receptors are coupled to guanine nucleotide-binding proteins (G-proteins).
Persistent Identifierhttp://hdl.handle.net/10722/224101
ISSN
2023 Impact Factor: 5.2
2023 SCImago Journal Rankings: 1.257
ISI Accession Number ID

 

DC FieldValueLanguage
dc.contributor.authorPang, CS-
dc.contributor.authorTang, PL-
dc.contributor.authorSong, Y-
dc.contributor.authorBrown, GM-
dc.contributor.authorPang, SF-
dc.date.accessioned2016-03-23T08:28:30Z-
dc.date.available2016-03-23T08:28:30Z-
dc.date.issued1996-
dc.identifier.citationLife Sciences, 1996, v. 58 n. 13, p. 1047-1057-
dc.identifier.issn0024-3205-
dc.identifier.urihttp://hdl.handle.net/10722/224101-
dc.description.abstractTo investigate whether melatonin has a direct action on the cardiovascular system, putative melatonin receptors were studied in quail heart membrane preparations using the specific melatonin agonist 2-[125I]iodomelatonin ([125I]Mel) as the radioligand. The [125I]Mel binding demonstrated in the mature quail heart was saturable, highly specific and reversible, of picomolar affinity and femtomolar density (Kd = 35.2 ±5.2 pM; Bmax = 1.32 ± 0.25 fmol/mg protein; n = 8). The linear Scatchard plots and the close to unity Hill coefficient indicated a single class of binding sites. The pharmacological profile was in the affinity order of 2-iodomelatonin = 2-phenylmelatonin > melatonin > 6-chloromelatonin ⪢ 6-hydroxymelatonin > 6-sulphatoxymelatonin ⪢ N-acetylserotonin ⋙ 5-hydroxytryptamine. Guanosine 5′- riphosphate and guanosine 5'-O-(3-thiotriphosphate) (GTPγS) dose dependently inhibited the binding. Ten μM GTPγS lowered the binding affinity by 50% in saturation studies. The order of potency of inhibition by cations was: Ca2+ > Mg2+ > Li+ > Na+ > K+ > cholinechloride. Contrary to most other melatonin binding sites, millimolar concentrations of Ca2+ and Mg2+ did not promote binding in the quail heart membranes. In vitro autoradiography indicated homogenous labeling in the heart. Our results demonstrated [125I]Mel binding sites in the quail heart. That guanine nucleotides and Na+ inhibited the binding indicated that these putative melatonin receptors are coupled to guanine nucleotide-binding proteins (G-proteins).-
dc.languageeng-
dc.publisherElsevier Inc. The Journal's web site is located at http://www.elsevier.com/locate/lifescie-
dc.relation.ispartofLife Sciences-
dc.rightsPosting accepted manuscript (postprint): © <year>. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/-
dc.subjectAutoradiography-
dc.subjectCalcium-
dc.subjectGuanine nucleotide-
dc.subjectMagnesium-
dc.subjectMelatonin receptor-
dc.subjectPineal gland-
dc.subjectPotassium-
dc.subjectSodium-
dc.subject.meshGuanosine 5'-O-(3-Thiotriphosphate) - pharmacology-
dc.subject.meshMagnesium Chloride - pharmacology-
dc.subject.meshMelatonin - analogs & derivatives - metabolism - pharmacology-
dc.subject.meshMyocardium - cytology - metabolism-
dc.subject.meshReceptors, Cell Surface - analysis - drug effects - metabolism-
dc.title2-[125I]Iodomelatonin binding sites in the quail heart: Characteristics, distribution and modulation by guanine nucleotides and cations-
dc.typeArticle-
dc.identifier.emailPang, SF: hrmypsf@hkucc.hku.hk-
dc.identifier.doi10.1016/0024-3205(96)00058-6-
dc.identifier.pmid8622557-
dc.identifier.scopuseid_2-s2.0-0029670240-
dc.identifier.hkuros25267-
dc.identifier.volume58-
dc.identifier.issue13-
dc.identifier.spage1047-
dc.identifier.epage1057-
dc.identifier.isiWOS:A1996TX08100004-
dc.publisher.placeHong Kong-
dc.identifier.issnl0024-3205-

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