Ventricular slices of adult mouse hearts--a new multicellular in vitro model for electrophysiological studies.
OBJECTIVE
We established a preparation of adult murine ventricular slices suitable for electrophysiological recordings as a new in vitro model of adult myocardium with preserved in vivo tissue structure.


METHODS
Short axis slices (thickness: 150 microm) of adult murine ventricles were prepared with a microtome. Sharp glass electrodes were used for measurements of action potentials (APs) at stimulation frequencies of 2 Hz and 10 Hz. Field potential (FP) recordings by means of microelectrode arrays (MEAs) were performed to map excitation spread.


RESULTS
APs showed the characteristics of adult murine ventricular APs: (i) a stable resting membrane potential, (ii) a fast upstroke and (iii) a fast phase 1 repolarization. Application of the Na+ channel blocker lidocaine (30 microM) led to a decline of upstroke slope, amplitude and conduction speed. The unspecific K+ channel blocker 4-aminopyridine (5 mM) caused a prolongation of APD50. The excitation spread was homogenous throughout the ventricular wall.


CONCLUSIONS
Adult murine ventricular slices are electrophysiologically intact and respond physiologically to cardioactive drugs. Thus, they provide a new multicellular in vitro model of adult cardiac tissue suitable for electrophysiological investigations, which in future could be used to study the functional integration of stem cells transplanted in infarcted hearts in vivo.
Halbach
Marcel
M
Department of Internal Medicine III, University of Cologne, Germany.
Pillekamp
Frank
F
Brockmeier
Konrad
K
Hescheler
Jürgen
J
Müller-Ehmsen
Jochen
J
Reppel
Michael
M
D000200:Action Potentials / Q000187:drug effects; D000631:Aminopyridines / Q000494:pharmacology; D000818:Animals; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods*; D006352:Heart Ventricles / Q000166:cytology; D066298:In Vitro Techniques; D008012:Lidocaine / Q000494:pharmacology; D051379:Mice; D015221:Potassium Channels / Q000502:physiology; D015222:Sodium Channels / Q000502:physiology; D016276:Ventricular Function
D000631:Aminopyridines; D015221:Potassium Channels; D015222:Sodium Channels; D008012:Lidocaine