[Electrical and contractile activity of the myocardium during a change in temperature]

In rhythmically stimulated (0.05/sec) isolated strips of the ventricle myocardium of the fresh water fish, drop of the temperature (from 20 degrees C to 10 degrees C) increased the AP duration but decreased the extent of contractions; raise of the temperature (from 10 degrees C to 20 degrees C) increased the extent of contractions but decreased the AP duration. The discrepancy between the electric and the contractile activities points out the importance of processes of the transmembrane and intracellular redistribution of ions occurring at rest, for refilling of intracellular Ca deposit released during excitation.