title: Anti-arrhythmic peptide N-3-(4-hydroxyphenyl)propionyl Pro-Hyp-Gly-Ala-Gly-OH reduces dispersion of action potential duration during ischemia/reperfusion in rabbit hearts.
abstract: During ischemia, cardiac gap junctions close and neighboring cells uncouple. This leads to slow conduction, increased dispersion of APD90 (duration from action potential beginning to 90% of repolarization), nonuniform anisotropy, and unidirectional conduction block, all of which favor the induction of reentry arrhythmias. It has been suggested that anti-arrhythmic peptides increase gap junction conductance during states of reduced coupling. The aim of this study was to test the effect of the anti-arrhythmic peptide N-3-(4-hydroxyphenyl)propionyl Pro-Hyp-Gly-Ala-Gly-OH (HP-5) (10(-10) ) on dispersion of epicardial APD90 during both normokalemic and hypokalemic ischemia/reperfusion in isolated perfused rabbit hearts. HP-5 did not affect average APD90, heart rate, left ventricular contractility (LVP dP/dtmax), or mean coronary flow. HP-5 significantly reduced the epicardial APD dispersion during hypokalemic ischemia (HP-5 treated: 24.1 +/- 3.4 ms, untreated: 33.9 +/- 3.1 ms, p < 0.05 versus untreated) and during normokalemic reperfusion but not during normokalemic ischemia or control conditions. In addition, among untreated hearts subjected to hypokalemic ischemia/reperfusion, seven of 10 developed ventricular fibrillation, whereas only three of nine hearts perfused with HP-5 developed ventricular fibrillation. These results show that HP-5 is able to reduce APD90 dispersion during hypokalemic ischemia in rabbit hearts.
authors.affiliation: Zealand Pharma, Glostrup, Denmark. alk@zp.dk
authors.forename: Anne Louise
authors.initials: AL
authors.lastname: Kjølbye
authors.forename: Niels-Henrik
authors.initials: NH
authors.lastname: Holstein-Rathlou
authors.forename: Jørgen Søberg
authors.initials: JS
authors.lastname: Petersen
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D004562:Electrocardiography; D004594:Electrophysiology; D006321:Heart / Q000502:physiology*; D006439:Hemodynamics / Q000187:drug effects*; D007511:Ischemia / Q000188:drug therapy*; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D011817:Rabbits; D023084:alpha-Defensins / Q000627:therapeutic use*
chemical_list: D000889:Anti-Arrhythmia Agents; D023084:alpha-Defensins; C406429:neutrophil peptide 5