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Article: Receptor-mediated modulation of avian caecal muscle contraction by melatonin: Role of tyrosine protein kinase

TitleReceptor-mediated modulation of avian caecal muscle contraction by melatonin: Role of tyrosine protein kinase
Authors
KeywordsCaecum
Gut
Melatonin
Receptor
Smooth muscle
Tyrosine kinase
Issue Date2002
PublisherBlackwell Munksgaard. The Journal's web site is located at http://www.blackwellpublishing.com/journals/JPI
Citation
Journal Of Pineal Research, 2002, v. 32 n. 3, p. 199-208 How to Cite?
AbstractMelatonin receptors in the quail caecum were studied by 2[125I]iodomelatonin binding assay and the involvement of tyrosine protein kinase in the melatonin-induced contraction was explored. The binding of 2[125I]iodomelatonin in the quail caecum membrane preparations was saturable, reversible and of high affinity with an equilibrium dissociation constant (Kd) of 24.6 ± 1.1 pm (n = 7) and a maximum number of binding sites (Bmax) of 1.95 ± 0.09 fmol (mg/protein) (n = 7). The relative order of potency of indoles in competing for 2[125I]iodomelatonin binding was: 2-iodomelatonin > melatonin > 2-phenylmelatonin > 6-chloromelatonin > 6-hydroxymelatonin > N-acetylserotonin, indicating that ML1 receptors are involved. The binding was inhibited by Mel1b melatonin receptor antagonists, luzindole and 4-phenyl-2-propionamidotetralin (4-P-PDOT) as well as by non-hydrolyzable analogs of GTP like GTPγS and Gpp(NH)p but hot by adenosine nucleotides. The latter suggests that the action ofmelatonin on the caecum is G-protein linked. Cumulative addition of melatonin (1-300 nM) potentiated both the amplitude and frequency of spontaneous contractions in the quail caecum. The potentiation of rhythmic contractions was blocked by both luzindole and 4-P-PDOT. Antagonists of tyrosine kinase, genistein(2 μM) and erbstatin(4 μM) suppressed the modulation of spontaneous contractions by melatonin, but hot inhibitors of protein kinase C (PKC) or protein kinase A (PKA). Melatonin-induced increment in spontaneous contraction was blocked by nifedipine (0.4 nM). Thus, we suggest that melatonin potentiates spontaneous contraction in the quail caecum via interacting with G-protein-coupled Mel1b receptor which may activate L-type Ca2+ channels by mobilizing tyrosine kinases.
Persistent Identifierhttp://hdl.handle.net/10722/81215
ISSN
2015 Impact Factor: 9.314
2015 SCImago Journal Rankings: 2.655
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorPoon, AMSen_HK
dc.contributor.authorKravtsov, GMen_HK
dc.contributor.authorPang, SFen_HK
dc.date.accessioned2010-09-06T08:15:07Z-
dc.date.available2010-09-06T08:15:07Z-
dc.date.issued2002en_HK
dc.identifier.citationJournal Of Pineal Research, 2002, v. 32 n. 3, p. 199-208en_HK
dc.identifier.issn0742-3098en_HK
dc.identifier.urihttp://hdl.handle.net/10722/81215-
dc.description.abstractMelatonin receptors in the quail caecum were studied by 2[125I]iodomelatonin binding assay and the involvement of tyrosine protein kinase in the melatonin-induced contraction was explored. The binding of 2[125I]iodomelatonin in the quail caecum membrane preparations was saturable, reversible and of high affinity with an equilibrium dissociation constant (Kd) of 24.6 ± 1.1 pm (n = 7) and a maximum number of binding sites (Bmax) of 1.95 ± 0.09 fmol (mg/protein) (n = 7). The relative order of potency of indoles in competing for 2[125I]iodomelatonin binding was: 2-iodomelatonin > melatonin > 2-phenylmelatonin > 6-chloromelatonin > 6-hydroxymelatonin > N-acetylserotonin, indicating that ML1 receptors are involved. The binding was inhibited by Mel1b melatonin receptor antagonists, luzindole and 4-phenyl-2-propionamidotetralin (4-P-PDOT) as well as by non-hydrolyzable analogs of GTP like GTPγS and Gpp(NH)p but hot by adenosine nucleotides. The latter suggests that the action ofmelatonin on the caecum is G-protein linked. Cumulative addition of melatonin (1-300 nM) potentiated both the amplitude and frequency of spontaneous contractions in the quail caecum. The potentiation of rhythmic contractions was blocked by both luzindole and 4-P-PDOT. Antagonists of tyrosine kinase, genistein(2 μM) and erbstatin(4 μM) suppressed the modulation of spontaneous contractions by melatonin, but hot inhibitors of protein kinase C (PKC) or protein kinase A (PKA). Melatonin-induced increment in spontaneous contraction was blocked by nifedipine (0.4 nM). Thus, we suggest that melatonin potentiates spontaneous contraction in the quail caecum via interacting with G-protein-coupled Mel1b receptor which may activate L-type Ca2+ channels by mobilizing tyrosine kinases.en_HK
dc.languageengen_HK
dc.publisherBlackwell Munksgaard. The Journal's web site is located at http://www.blackwellpublishing.com/journals/JPIen_HK
dc.relation.ispartofJournal of Pineal Researchen_HK
dc.subjectCaecumen_HK
dc.subjectGuten_HK
dc.subjectMelatoninen_HK
dc.subjectReceptoren_HK
dc.subjectSmooth muscleen_HK
dc.subjectTyrosine kinaseen_HK
dc.titleReceptor-mediated modulation of avian caecal muscle contraction by melatonin: Role of tyrosine protein kinaseen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0742-3098&volume=32&spage=199&epage=208&date=2002&atitle=Receptor+mediated+modulation+of+avian+caecal+muscle+contraction+by+melatonin:+Role+of+tyrosine+protein+kinaseen_HK
dc.identifier.emailPoon, AMS: amspoon@hkucc.hku.hken_HK
dc.identifier.authorityPoon, AMS=rp00354en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1034/j.1600-079x.2002.1o857.xen_HK
dc.identifier.pmid12074105-
dc.identifier.scopuseid_2-s2.0-0036224023en_HK
dc.identifier.hkuros72786en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0036224023&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume32en_HK
dc.identifier.issue3en_HK
dc.identifier.spage199en_HK
dc.identifier.epage208en_HK
dc.identifier.isiWOS:000175102200011-
dc.publisher.placeDenmarken_HK
dc.identifier.scopusauthoridPoon, AMS=7103068868en_HK
dc.identifier.scopusauthoridKravtsov, GM=7003811092en_HK
dc.identifier.scopusauthoridPang, SF=7402528719en_HK

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