Oxidized low density lipoproteins exert arrhythmogenic effects in rabbit Purkinje fibers.
The electrophysiological effects of oxidized low density lipoproteins (ox-LDLs) have been studied in rabbit Purkinje fibers using standard microelectrode techniques, in comparison with native LDLs (n-LDLs) and lysophosphatidylcholine (LPC). At the concentration of 100 micrograms protein/ml, ox-LDL but never n-LDL induced the abrupt occurrence of abnormal electrical activities during the basic stimulation of 1 Hz (6/13 fibers) and the development of either early afterdepolarizations (6/13 fibers) or abnormal automaticity (4/13 fibers) at low frequencies (0.1 and 0.03 Hz). Short trains of rapid stimulation (2, 3, 4 and 5 Hz) did not trigger delayed afterdepolarizations. However, early afterhyperpolarizations were commonly seen after each action potential. 30 microM LPC caused quite similar electrophysiological derangements. The results suggest that ox-LDLs may exert arrhythmogenic effects partly explained by their LPC content.
Adamantidis
M M
MM
Laboratoire de Pharmacologie, Faculté de Médecine, Lille, France.
Moreau-Guedon
L
L
Martin-Nizard
F
F
Sqalli-Houssaini
H
H
Duriez
P
P
Fruchart
J C
JC
Dupuis
B
B
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D004558:Electric Stimulation; D006339:Heart Rate / Q000187:drug effects*; D006352:Heart Ventricles; D006801:Humans; D066298:In Vitro Techniques; D008077:Lipoproteins, LDL / Q000097:blood / Q000302:isolation & purification / Q000494:pharmacology*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D010084:Oxidation-Reduction; D011690:Purkinje Fibers / Q000187:drug effects / Q000502:physiology*; D011817:Rabbits
D008077:Lipoproteins, LDL