| Abstract: | Single myocardial cells from fetal mouse heart beat spontaneously in monolayer culture. In standard medium they maintained constant beating rates for at least 5 h at 37 °C. When the beats of single myocardial cells were stopped for a short time by treatment with EGTA, or slowed down by incubating the cells in medium of low pH, the original beating rates could be restored by replacing the cells in the original medium. The same procedure also restored the rates after they had been disturbed by incubating the cells in medium of low sodium and high potassium ion content. Moreover, the original beating rates could be restored after keeping the cells at 10 °C for 22–24 h, but not after keeping them at 37 °C for 22–24 h. |
