The intricate anatomy of the myocardium, coupled with distinct morphology and function of specialized component cells, often presents acute problems in the inter- pretation of experimental data obtained from the whole organ. One experimental approach to minimize some of the difficulties encountered is the use of single cardiac cells isolated enzymically from adult mammalian myocardium and a technique has been developed in this laboratory whereby tissue dissociation is achieved by in vitro organ perfusion with crude bacterial collagenase (Gould & Powell, 1972;
Powell & Twist, 1976a). Myocytes isolated in this manner from adult rat heart have ntypical superficial and subcellular morphology (Gould & Powell, 1972; Powell, Steen, Twist & Woolf, 1978a), show respiratory coupling (Powell & Twist, 1975, 1976a) and have retained responsiveness to fi-adrenergic stimulation (Powell & Twist, 1976b; Powell, Terrar & Twist, 1978c). To date, however, there has been no systematic study of the electrical activity of these isolated cells, although such data are central to both the evaluation of the preparation as a useful experimental model and also to gain an insight into the electrophysiology of cardiac cells uncoupled physically from their usual syncitial state.
Experiments are presented to show that under suitable incubation conditions membrane potentials which are comparable to those reported for multicellular preparations can be recorded from isolated cells using intracellular micro-electrodes. It is also demonstrated that these cells can generate conventional action potentials, indicating that the relevant ionic mechanisms have been preserved during the iso- lation procedures. Some of these results have appeared previously in abstract form (Powell, Terrar & Twist, 1978b, c).
Xanya Sofra Weiss
Xanya Sofra Weiss
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