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Conference Paper: An anti-adrenergic effect of melatonin on quail caecal smooth muscle: relationship between protein kinase A and tyrosine kinase

TitleAn anti-adrenergic effect of melatonin on quail caecal smooth muscle: relationship between protein kinase A and tyrosine kinase
Authors
Issue Date1999
PublisherS Karger AG. The Journal's web site is located at http://www.karger.com/NSG
Citation
The 1999 Annual Physiology Symposium, Hong Kong, China, 21-22 May 1999. In Biological Signals and Receptors, 1999, v. 8 n. 3, p. 203-204 How to Cite?
AbstractBinging of 2[125I]-iodomelatonin, a specific melatonin agonist, to the quail caecum was studied. In addition, the effect of melatonin on the spontaneous contractile response in quail caecum and the possible mechanism of melatonin action involved were explored. A single population of specific and high affinity binding sites for melatonin (Kd = 24.6 B 1.1 pmol/l, n = 4; Bmax = 2.0 B 0.1 fmol/mg, n = 7) has been revealed in the crude caecal membrane preparation. Under an in vitro system, low concentrations of melatonin (1 pM–100 nM) potentiated the amplitude and frequency of spontaneous contractile responses in caecal rings and strips. This effect of melatonin was prevented by preincubation of the muscle preparation with a specific inhibitor of tyrosine kinase genistein (2 ÌM). In contrast to melatonin, agents such as epinephrine (10 nM), and isoproterenol (10 nM), which are known to increase the level of the intracellular cAMP and thereby activating protein kinase A, or dibutyryl-cAMP (1 mM), completely blocked the spontaneous contractions. The inhibitory influence of ß-agonists on contractions in caecum rings was partly reversed by the application of melatonin (0.1–1 ÌM). Epidermal growth factor (EGF) (0.2 Ìg/ml) which is linked to receptor-dependent tyrosine kinase, similar to melatonin, also restored the isoproterenol-induced suppression of spontaneous contractions. Neither melatonin nor EGF was able to modify isoproterenol-induced inhibition in genistein-treated caecum rings. It is concluded that melatonin has an anti-adrenergic action on the quail smooth muscle and this seems to be a receptor-mediated response. Moreover, the effect may be coupled to an activation of tyrosine kinase, which is likely to antagonize the influence of protein kinase A.
Descriptionpp. 193–220 of this journal entitled: Annual Physiology Symposium 1999
Persistent Identifierhttp://hdl.handle.net/10722/105313
ISSN
2003 Impact Factor: 3.5

 

DC FieldValueLanguage
dc.contributor.authorKravtsov, GMen_HK
dc.contributor.authorPoon, AMSen_HK
dc.contributor.authorPang, SFen_HK
dc.date.accessioned2010-09-25T22:28:52Z-
dc.date.available2010-09-25T22:28:52Z-
dc.date.issued1999en_HK
dc.identifier.citationThe 1999 Annual Physiology Symposium, Hong Kong, China, 21-22 May 1999. In Biological Signals and Receptors, 1999, v. 8 n. 3, p. 203-204en_HK
dc.identifier.issn1422-4933en_HK
dc.identifier.urihttp://hdl.handle.net/10722/105313-
dc.descriptionpp. 193–220 of this journal entitled: Annual Physiology Symposium 1999-
dc.description.abstractBinging of 2[125I]-iodomelatonin, a specific melatonin agonist, to the quail caecum was studied. In addition, the effect of melatonin on the spontaneous contractile response in quail caecum and the possible mechanism of melatonin action involved were explored. A single population of specific and high affinity binding sites for melatonin (Kd = 24.6 B 1.1 pmol/l, n = 4; Bmax = 2.0 B 0.1 fmol/mg, n = 7) has been revealed in the crude caecal membrane preparation. Under an in vitro system, low concentrations of melatonin (1 pM–100 nM) potentiated the amplitude and frequency of spontaneous contractile responses in caecal rings and strips. This effect of melatonin was prevented by preincubation of the muscle preparation with a specific inhibitor of tyrosine kinase genistein (2 ÌM). In contrast to melatonin, agents such as epinephrine (10 nM), and isoproterenol (10 nM), which are known to increase the level of the intracellular cAMP and thereby activating protein kinase A, or dibutyryl-cAMP (1 mM), completely blocked the spontaneous contractions. The inhibitory influence of ß-agonists on contractions in caecum rings was partly reversed by the application of melatonin (0.1–1 ÌM). Epidermal growth factor (EGF) (0.2 Ìg/ml) which is linked to receptor-dependent tyrosine kinase, similar to melatonin, also restored the isoproterenol-induced suppression of spontaneous contractions. Neither melatonin nor EGF was able to modify isoproterenol-induced inhibition in genistein-treated caecum rings. It is concluded that melatonin has an anti-adrenergic action on the quail smooth muscle and this seems to be a receptor-mediated response. Moreover, the effect may be coupled to an activation of tyrosine kinase, which is likely to antagonize the influence of protein kinase A.-
dc.languageengen_HK
dc.publisherS Karger AG. The Journal's web site is located at http://www.karger.com/NSGen_HK
dc.relation.ispartofBiological Signals and Receptorsen_HK
dc.rightsBiological Signals and Receptors. Copyright © S Karger AG.en_HK
dc.titleAn anti-adrenergic effect of melatonin on quail caecal smooth muscle: relationship between protein kinase A and tyrosine kinaseen_HK
dc.typeConference_Paperen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1422-4933&volume=8&spage=203&epage=&date=1999&atitle=An+Anti-adrenergic++Effect+of+Melatonin+on+Quail+Caecal+Smooth+Muscle:+Relationship+between+Protein+Kinase+A+and+Tyrosine+Kinaseen_HK
dc.identifier.emailKravtsov, GM: gmkravts@HKUCC.hku.hken_HK
dc.identifier.emailPoon, AMS: amspoon@hkucc.hku.hken_HK
dc.identifier.emailPang, SF: hrmypsf@hkucc.hku.hken_HK
dc.identifier.authorityPoon, AMS=rp00354en_HK
dc.identifier.doi10.1159/000014590-
dc.identifier.hkuros44155en_HK
dc.identifier.volume8en_HK
dc.identifier.issue3-
dc.identifier.spage203en_HK
dc.identifier.epage204-
dc.publisher.placeSwitzerland-

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