Differential role of sarcolemmal and mitochondrial K(ATP) channels in adenosine-enhanced ischemic preconditioning.
Adenosine-enhanced ischemic preconditioning (APC) extends the protection afforded by ischemic preconditioning (IPC) by both significantly decreasing infarct size and significantly enhancing postischemic functional recovery. The purpose of this study was to determine whether APC is modulated by ATP-sensitive potassium (K(ATP)) channels and to determine whether this modulation occurs before ischemia or during reperfusion. The role of K(ATP) channels before ischemia (I), during reperfusion (R), or during ischemia and reperfusion (IR) was investigated using the nonspecific K(ATP) blocker glibenclamide (Glb), the mitochondrial (mito) K(ATP) channel blocker 5-hydroxydecanoate (5-HD), and the sarcolemmal (sarc) K(ATP) channel blocker HMR-1883 (HMR). Infarct size was significantly increased (P < 0.05) in APC hearts with Glb-I, Glb-R, and 5-HD-I treatment and partially with 5-HD-R. Glb-I and Glb-R treatment significantly decreased APC functional recovery (P < 0.05 vs. APC), whereas 5-HD-I and 5-HD-R had no effect on APC functional recovery. HMR-IR significantly decreased postischemic functional recovery (P < 0.05 vs. APC) but had no effect on infarct size. These data indicate that APC infarct size reduction is modulated by mitoK(ATP) channels primarily during ischemia and suggest that functional recovery is modulated by sarcK(ATP) channels during ischemia and reperfusion.
Toyoda
Y
Y
Division of Cardiothoracic Surgery and Biometrics Center, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02115, USA.
Friehs
I
I
Parker
R A
RA
Levitsky
S
S
McCully
J D
JD
D000241:Adenosine / Q000494:pharmacology*; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D003652:Decanoic Acids / Q000494:pharmacology; D005905:Glyburide / Q000494:pharmacology; D006880:Hydroxy Acids / Q000494:pharmacology; D007004:Hypoglycemic Agents / Q000494:pharmacology; D066298:In Vitro Techniques; D019157:Ischemic Preconditioning, Myocardial; D008928:Mitochondria / Q000378:metabolism*; D017682:Myocardial Stunning / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000502:physiology*; D011817:Rabbits; D012508:Sarcolemma / Q000378:metabolism*; D013449:Sulfonamides / Q000494:pharmacology; D013890:Thiourea / Q000031:analogs & derivatives* / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*
D000889:Anti-Arrhythmia Agents; D003652:Decanoic Acids; D006880:Hydroxy Acids; D007004:Hypoglycemic Agents; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D013449:Sulfonamides; D014665:Vasodilator Agents; C052853:5-hydroxydecanoic acid; C114623:clamikalant; D013890:Thiourea; D000241:Adenosine; D005905:Glyburide; D002118:Calcium