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Pacemaker activity and mitosis in cultures of newborn rat heart ventricle cells

1966; Elsevier BV; Volume: 44; Issue: 2-3 Linguagem: Inglês

10.1016/0014-4827(66)90427-7

1090-2422

Gerda E. Mark, Florian Strasser,

Cardiomyopathy and Myosin Studies

1. A reproducible culture system has been described in which single newborn rat heart ventricle cells develop into a differentiated, synchronously-beating network and continue to function for many weeks with no evidence of dedifferentiation and no loss of beating rate. This system allows excellent optical resolution of cell morphology and behavior. 2. Contrary to the accepted idea that only the "pacemaker" cells of the heart may initiate beating, our results indicate that, in tissue culture, all muscle cells of the newborn rat heart ventricle appear to be capable of independent and spontaneous contraction. The rate of beating varies widely from cell to cell. The possible significance of this in relation to the embryological development of the heart has been discussed. 3. The protoplasmic connection necessary for synchronization of beating need not be directly from one muscle cell to another, but may be made through the non-muscle cells, probably of endothelial origin. Synchronization upon cell contact (as defined by high resolution phase microscopy) is rapid but not instantaneous, the faster-beating cell acting as pacemaker. 4. Heart muscle cells may undergo mitosis while continuing to beat. The mitosis appears to be modified to insure the continued function of the cell as part of a tissue unit during this process. 5. A double membrane surrounding the nucleus of all heart muscle cells, and clearly visible with the phase microscope, has been observed.