Calcium-dependent action potentials elicited in the lizard ventricle by a prolonged hypothermic incubation

After a prolonged hypothermic incubation (48 h at 4 degrees C), lizard ventricles perfused with a solution containing 15 mM k+ and 1 mM Ca2+ exhibit slow responses, which are similar (prescinding from their noticeable greater duration) to the responses which can be elicited, in the same depolarizing solution, by increasing the external calcium concentration or by adding catecholamines to the perfusing medium. The phenomenon is transient, and vanishes within 90 min from the end of the hypothermia.