Calcium Preconditioning, but Not Ischemic Preconditioning, Bypasses the Adenosine Triphosphate-Dependent Potassium (KATP) Channel

The L‐Type Ca2+ and KATP Channels May Contribute to Pacing‐Induced Protection Against Anoxia‐Reoxygenation in the Embryonic Heart Model

“…Besides the classical ischemic preconditioning, Ca 2+ by itself could play a major role in myocardial preconditioning, directly or as a second messenger altering gene expression. 15 Furthermore, ischemic preconditioning is inhibited by L-type Ca 2+ channel blockers. 17 In our model, the Ca 2+ change induced by pacing was expected to be small, much less than a Ca 2+ overload, since we observed no additional contracture and no significant shortening aleration in paced hearts relative to sham, whatever the treatment.…”

“…Besides the classical ischemic preconditioning, Ca 2+ by itself could play a major role in myocardial preconditioning, directly or as a second messenger altering gene expression 15 . Furthermore, ischemic preconditioning is inhibited by L‐type Ca 2+ channel blockers 17 .…”

“…12 Similarly, it has been recently shown that dyssynchronous ventricular activation at physiological rate can also precondition the adult heart (rabbit) against ischemia-reperfusion injury. 13 The role played by the L-type Ca 2+ channel, the sarcolemmal (sarcK ATP ), and mitochondrial K ATP (mitoK ATP ) channels, known otherwise to be involved in ischemic and pharmacological preconditioning, [14][15][16][17] remains to be investigated in the pacing-induced protection. Using the embryonic chick heart model, we aimed at determining to what extent pharmacological modulation of these channels affects the protection against posthypoxic injury afforded by pacing at near physiological rate.…”