title: Influence of mechanical activity, adrenergic stimulation, and calcium on the expression of myosin heavy chains in cultivated neonatal cardiomyocytes.
abstract: It is generally accepted that mechanical stress of cardiomyocytes increases RNA and protein synthesis of myosin heavy chain (MHC) quantitatively but it is still a matter of debate whether MHC gene expression is also changed qualitatively. We investigated expression of MHC genes of spontaneously contracting neonatal cardiomyocytes experimentally arrested by permanent depolarization [potassium chloride (KCl)] as well as by electromechanical uncoupling [2,3 butanedione monoxime (BDM)]. Relative distribution of MHC mRNA isoforms (alpha and beta) was studied by quantitative polymerase chain reaction. Expression of MHC isoenzymes was the same in contracting (34.5% beta-MHC) and arrested (40.5% and 33.0% beta-MHC in KCl and BDM, respectively) cardiomyocytes. However, treatment with phenylephrine for the same period increased significantly beta-MHC expression to 55%. We conclude that hormonal factors rather than Ca2+ or mechanical stress regulate qualitatively MHC gene expression.
authors.affiliation: Max Delbrück Centre for Molecular Medicine, Berlin, Germany.
authors.forename: H P
authors.initials: HP
authors.lastname: Luther
authors.forename: S
authors.initials: S
authors.lastname: Hille
authors.forename: H
authors.initials: H
authors.lastname: Haase
authors.forename: I
authors.initials: I
authors.lastname: Morano
mesh_terms: D018663:Adrenergic Agents / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002478:Cells, Cultured; D017931:DNA Primers; D003931:Diacetyl / Q000031:analogs & derivatives / Q000494:pharmacology; D005786:Gene Expression Regulation; D009206:Myocardium / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011189:Potassium Chloride / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017422:Sequence Analysis, DNA; D014158:Transcription, Genetic
chemical_list: D018663:Adrenergic Agents; D017931:DNA Primers; D012333:RNA, Messenger; C004717:diacetylmonoxime; D011189:Potassium Chloride; D018995:Myosin Heavy Chains; D003931:Diacetyl; D002118:Calcium