Scarparo, Ana CristinaSumida, Doris Hissako [UNESP]Patrão, Marília T. C. C.Avellar, Maria Christina W.Visconti, Maria AparecidaCastrucci, Ana Maria de Lauro2014-05-272014-05-272004-08-01Archives of Dermatological Research, v. 296, n. 3, p. 112-119, 2004.0340-3696http://hdl.handle.net/11449/67806The biological effects of catecholamines in mammalian pigment cells are poorly understood. Our previous results showed the presence of α1-adrenoceptors in SK-Mel 23 human melanoma cells. The aims of this work were to (1) characterize catecholamine effects on proliferation, tyrosinase activity and expression, (2) identify the α1- adrenoceptor subtypes, and (3) verify whether chronic norepinephrine (NE) treatment modified the types and/or pharmacological characteristics of adrenoceptors present in SK-Mel 23 human melanoma cells. Cells treated with the aradrenergic agonist, phenylephrine (PHE, 10-5 or 10-4 M), for 24-72 h, exhibited decreased cell proliferation and enhanced tyrosinase activity, but unaltered tyrosinase expression as compared with the control. The proliferation and tyrosinase activity responses were inhibited by the α1-adrenergic antagonist prazosin, suggesting they were evoked by α1-adrenoceptors. The presence of actinomycin D, a transcription inhibitor, did not diminish PHE-induced effects. RT-PCR assays, followed by cloning and sequencing, demonstrated the presence of α1A- and α1B-adrenoceptor subtypes. NE-treated cells (24 or 72 h) were used in competition assays, and showed no significant change in the competition curves of α1-adrenoceptors as compared with control curves. Other adrenoceptor subtypes were not identified in these cells, and NE pretreatment did not induce their expression. In conclusion, the activation of SK-Mel 23 human melanoma α1- radrenoceptors elicit biological effects, such as proliferation decrease and tyrosinase activity increase. Desensitization or expression of other adrenoceptor subtypes after chronic NE treatment were not observed.112-119engα1-AdrenoceptorsCatecholaminesCell proliferationSK-Mel 23 melanoma cellsTyrosinase activityalpha 1 adrenergic receptoralpha 1 adrenergic receptor blocking agentalpha 1 adrenergic receptor stimulating agentascorbic acidbenoxathiancatecholaminedactinomycinmonophenol monooxygenasenoradrenalinphenylephrineprazosinadrenergic systemcatecholamine metabolismcell proliferationcell strain SK Mel 23controlled studyenzyme activityhumanhuman cellmelanoma cellpigment cellpriority journalreverse transcription polymerase chain reactionWestern blottingAdrenergic alpha-AgonistsBinding, CompetitiveCell DivisionCell Line, TumorGene ExpressionHumansMelanomaMonophenol MonooxygenaseNorepinephrinePhenylephrineReceptors, Adrenergic, alpha-1Skin NeoplasmsArtigo10.1007/s00403-004-0488-xAcesso restrito2-s2.0-43446342808275401688702343