Alloxan-diabetic state-induced suppression of Ca2+-dependent slow action potentials in mouse diaphragm muscle.

Ca2+-dependent slow action potentials (AP) were investigated in diaphragm muscles of alloxan-diabetic mice in comparison with normal muscles. Slow APs observed in diabetic muscles were significantly decreased in amplitude and duration. The slow APs which were generated at a stimulation frequency of once every 15 sec decayed more rapidly in diabetic muscles. Fatigue, however, developed regardless of the presence of verapamil (10 microM) in contrast to the quicker development of fatigue in normal muscles in response to verapamil.