Cardiac hypoxia and subsequent reoxygenation: sensitivity to L-arginine methylester.
The effect of L-arginine methylester (L-Arg-Me) was studied in the isolated heart of the guinea-pig perfused with hypoxic substrate-free medium for 30 min and subsequently reoxygenated with normal saline solution for 30 min. The administration of L-Arg-Me in basal conditions decreases dose-dependently heart rate without any changes in the myocardial structure. On the other hand, the administration of L-Arg-Me (5-10 mM) decreases ventricular arrhythmias, especially during reoxygenation; in fact ventricular fibrillation is abolished. L-Arg-Me treatment increases the recovery of normal electrical and mechanical activity at the end of reoxygenation and reduces the increase in basal tone. Treatment with 10 mM L-Arg-Me decreases lactate dehydrogenase (LDH) release in the effluent and lysosomal fragility in cardiac tissue, while it does not influence calcium gain. L-Arginine (L-Arg) does not mimic any of the effects of L-Arg-Me.
C
C
Baccaro
F
F
Bennardini
G
G
Dini
F
F
Franconi
A
A
Giotti
R
R
Matucci
P
P
Minuti
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002402:Cathepsin D / Q000378:metabolism; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism* / Q000648:ultrastructure; D010100:Oxygen / Q000494:pharmacology*; D010477:Perfusion
C026512:arginine methyl ester; D001120:Arginine; D007770:L-Lactate Dehydrogenase; D002402:Cathepsin D; D010100:Oxygen; D002118:Calcium