title: Cardioprotection of electroacupuncture against myocardial ischemia-reperfusion injury by modulation of cardiac norepinephrine release.
abstract: Augmentation of cardiac sympathetic tone during myocardial ischemia has been shown to increase myocardial O(2) demand and infarct size as well as induce arrhythmias. We have previously demonstrated that electroacupuncture (EA) inhibits the visceral sympathoexcitatory cardiovascular reflex. The purpose of this study was to determine the effects of EA on left ventricular (LV) function, O(2) demand, infarct size, arrhythmogenesis, and in vivo cardiac norepinephrine (NE) release in a myocardial ischemia-reperfusion model. Anesthetized rabbits (n = 36) underwent 30 min of left anterior descending coronary artery occlusion followed by 90 min of reperfusion. We evaluated myocardial O(2) demand, infarct size, ventricular arrhythmias, and myocardial NE release using microdialysis under the following experimental conditions: 1) untreated, 2) EA at P5-6 acupoints, 3) sham acupuncture, 4) EA with pretreatment with naloxone (a nonselective opioid receptor antagonist), 5) EA with pretreatment with chelerythrine (a nonselective PKC inhibitor), and 6) EA with pretreatment with both naloxone and chelerythrine. Compared with the untreated and sham acupuncture groups, EA resulted in decreased O(2) demand, myocardial NE concentration, and infarct size. Furthermore, the degree of ST segment elevation and severity of LV dysfunction and ventricular arrhythmias were all significantly decreased (P < 0.05). The cardioprotective effects of EA were partially blocked by pretreatment with naloxone or chelerythrine alone and completely blocked by pretreatment with both naloxone and chelerythrine. These results suggest that the cardioprotective effects of EA against myocardial ischemia-reperfusion are mediated through inhibition of the cardiac sympathetic nervous system as well as opioid and PKC-dependent pathways.
authors.affiliation: Department of Anesthesiology, David Geffen School Medicine, University of California, Los Angeles, California 90095, USA. wzhou@mednet.ucla.edu
authors.forename: Wei
authors.initials: W
authors.lastname: Zhou
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Ko
authors.forename: Peyman
authors.initials: P
authors.lastname: Benharash
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamakawa
authors.forename: Sunny
authors.initials: S
authors.lastname: Patel
authors.forename: Olujimi A
authors.initials: OA
authors.lastname: Ajijola
authors.forename: Aman
authors.initials: A
authors.lastname: Mahajan
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000517:prevention & control; D053119:Benzophenanthridines / Q000494:pharmacology; D015671:Electroacupuncture; D023421:Models, Animal; D009203:Myocardial Infarction / Q000473:pathology; D015428:Myocardial Reperfusion Injury / Q000378:metabolism* / Q000473:pathology / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism*; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists; D009638:Norepinephrine / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013564:Sympathetic Nervous System / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology
chemical_list: D053119:Benzophenanthridines; D009292:Narcotic Antagonists; D009270:Naloxone; C016299:chelerythrine; D011493:Protein Kinase C; D010100:Oxygen; D009638:Norepinephrine