title: Electrophysiology of adult cat cardiac ventricular myocytes: changes during primary culture.
abstract: To investigate the nature of electrophysiological changes in adult cat cardiac ventricular myocytes that may occur when cells are maintained in primary culture for 1-2 wk, the electrophysiology of cells freshly isolated from collagenase-perfused hearts (day 0 controls) was compared with that of cells maintained in primary culture for up to 14 days 1) on a two-dimensional (2D) surface (laminin-coated coverslips), which allowed for changes in cellular morphology, or 2) in a three-dimensional (3D) alginate matrix, which minimized changes in cell shape. Action potentials and whole cell ionic currents were recorded using a conventional whole cell patch technique. Whereas cellular resting potential and the depth of the "notch" terminating phase 1 were diminished relative to controls in 2D- and 3D-cultured cells, the action potential duration and the incidence of early afterdepolarizations (EADs) were increased relative to controls in 2D- but not in 3D-cultured cells. Corresponding alterations in whole cell ionic currents included a 40% reduction in inwardly rectifying K current (IK1) conductance (GK1) and a 90% reduction in transient outward K current (Ito) conductance (Gto) in 2D- and 3D-cultured cells relative to day 0 controls and a 50% increase in L-type Ca current (ICa-L) conductance (GCa-L) in 2D-cultured cells relative to 3D-cultured cells and day 0 controls. The reduction in Gto in long-term culture was half-maximal by days 7 and 8 and could not be attributed to reduced Ito availability, involvement of a noninactivating Ito, the cell culture procedure itself, or the presence of serum in the culture media. Gto was larger in day 0 cells from a heart with right ventricular hypertrophy than in day 0 normal control cells and was reduced subsequent to placement of cells in 3D culture for 19 days. The results suggest that long-term culture and change in cellular morphology can affect the electrophysiology of cardiac ventricular myocytes.
authors.affiliation: Department of Molecular Pharmacology and Biological Chemistry, Northwestern University, Chicago, Illinois 60611, USA.
authors.forename: T E
authors.initials: TE
authors.lastname: Schackow
authors.forename: R S
authors.initials: RS
authors.lastname: Decker
authors.forename: R E
authors.initials: RE
authors.lastname: Ten Eick
mesh_terms: D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000502:physiology; D002415:Cats; D002478:Cells, Cultured; D004594:Electrophysiology; D008955:Models, Cardiovascular; D009206:Myocardium / Q000166:cytology*; D011188:Potassium / Q000502:physiology; D016276:Ventricular Function
chemical_list: D011188:Potassium; D002118:Calcium