127 Original Paper Cell Physiol Biochem 2005;16:127-132 Accepted: April 18, 2005 Cellular Physiology Cellular Physiology Cellular Physiology Cellular Physiology Cellular Physiology and Biochemistr and Biochemistr and Biochemistr and Biochemistr and Biochemistry Copyright © 2005 S. Karger AG, Basel Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com © 2005 S. Karger AG, Basel 1015-8987/05/0163-0127$22.00/0 Accessible online at: www.karger.com/journals/net Establishment and Characterization of a Mouse Embryonic Heart Slice Preparation Frank Pillekamp, M.D. 1,2,a , Michael Reppel, M.D. 2,a , Vera Dinkelacker, M.D. 3,4 , Yaqi Duan 2 , Nathalie Jazmati 2 , Wilhelm Bloch, M.D. 5 , Konrad Brockmeier, M.D. 1 , Juergen Hescheler, M.D. 2 , Bernd K. Fleischmann, M.D. 3 and Ruediger Koehling, M.D. 4 1 Pediatric Cardiology and 2 Institute of Neurophysiology, University of Cologne, 3 Institute of Physiology I and 4 Department of Epileptology, University of Bonn, 5 Department of Molecular and Cellular Sport Medicine, German Sport University, Cologne, a authors contributed equally to the manuscript Bernd K. Fleischmann, M.D. Institute of Physiology I, Live & Brain Center, University of Bonn Sigmund-Freud-Str. 25, D-53105 Bonn (Germany) Tel. +49-228-6885-200, Fax +49-228-6885-201 E-Mail bernd.fleischmann@uni-bonn.de Key Words Myocytes, cardiac/*physiology  Action potentials  Electrophysiology/*methods  Electrophysiology/ *embryology  Heart/*physiology  Animal models Abstract Background: In contrast to isolated cells, the anatomic and functional integrity of tissue slices remains preserved. Aim of the study was to establish the slice technique in embryonic mouse hearts in order to perform physiological and pharmacological investigations of wild-type mice and genetically engineered mouse models of heart disease. Methods: Ventricular slices (thickness: 300 µm) were cut from agar-embedded embryonic mouse hearts (ED 16.5- 18.5) with a vibratome. Histology, immunostaining with markers for apoptosis induction, intracellular recordings with sharp electrodes and field potential recordings using microelectrode arrays were performed to assess viability. Results: Slices exhibited normal histology without prominent signs of apoptosis for at least 24 hours. Intracellular recordings revealed the typical electrophysiological fingerprint of ventricular cardiomyocytes. Field potential recordings proved that adrenergic and muscarinic signaling was preserved. Conclusion: Functionally intact heart slices can be generated from murine embryos. Introduction The advent of the brain slice preparation led to a dramatic improvement of the understanding of cerebral activity because it has enabled studies of cellular function in the context of an intact tissue [1]. This is particularly important for structures like the brain and the heart in which intercellular cross-talk is critical for complex organ function. Furthermore, aggressive dissociation methods required to prepare isolated cells, often have adverse effects on the function of ion channels and receptors. Thus, we sought to establish an intact heart slice preparation so that we might better understand mechanisms of cardiac physiology in the future. To date, relatively little progress has been made in establishing a viable heart slice preparation [2, 3] and in recording physiological activity of cardiac slices [4]. This is in part due to the fact that the heart contains a significant amount