title: Adult rat ventricular myocytes cultured in defined medium: phenotype and electromechanical function.
abstract: We studied primary short-term cultures of adult rat ventricular myocytes in defined medium to determine whether phenotype and electromechanical function are maintained in rod-shaped, quiescent cells. Although > 80% of the myocytes retained their rod-shaped in vivo morphology for up to 72 h, contractile function as measured by cell edge motion declined 30-50% from 6 to 24 h, paralleling a 68% shortening of action potential duration. From 24 to 72 h, contractility remained unchanged. Ca2+ channel current density increased 55% after 24-48 h and then returned to the level of freshly isolated cells (9 +/- 1 pA/pF, mean +/- SE). Resting membrane potential (-71 +/- 1 mV) and action potential overshoot (34 +/- 3 mV) did not change. The ratio of alpha- to beta-myosin heavy chain mRNA and the level of cardiac alpha-actin mRNA were maintained for 8 days. Thus quiescent adult rat ventricular myocytes in defined medium undergo extensive phenotypic adaptation within 72 h of isolation, despite maintenance of a rod-shaped morphology and stable levels of contractile protein mRNA, which may limit their suitability for electrophysiological and contractile function studies.
authors.affiliation: Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts 02115.
authors.forename: O
authors.initials: O
authors.lastname: Ellingsen
authors.forename: A J
authors.initials: AJ
authors.lastname: Davidoff
authors.forename: S K
authors.initials: SK
authors.lastname: Prasad
authors.forename: H J
authors.initials: HJ
authors.lastname: Berger
authors.forename: J P
authors.initials: JP
authors.lastname: Springhorn
authors.forename: J D
authors.initials: JD
authors.lastname: Marsh
authors.forename: R A
authors.initials: RA
authors.lastname: Kelly
authors.forename: T W
authors.initials: TW
authors.lastname: Smith
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology; D002470:Cell Survival; D002478:Cells, Cultured; D003470:Culture Media; D004594:Electrophysiology; D015870:Gene Expression; D006321:Heart / Q000502:physiology*; D006352:Heart Ventricles; D009200:Myocardial Contraction; D009206:Myocardium / Q000166:cytology*; D010641:Phenotype; D051381:Rats
chemical_list: D003470:Culture Media; D002118:Calcium