Effects of alpha adrenergic blockade during stellate ganglion stimulation on arrhythmias induced by acute myocardial ischemia in pigs.
The effects of alpha-adrenergic receptor blockade during stellate ganglion stimulation on arrhythmias induced by repeated coronary artery occlusion in pigs under spontaneous breathing were studied. Prazosin, alpha 1-receptor blocker, did not have any effect on the early ischemic dysrhythmia. Yohimbine, which selectively blocks alpha 2-receptor, significantly increased the number of premature ventricular complexes (19 +/- 3----32 +/- 2 PVC; P less than 0.01), but produced no effects on the percentage of appearance of ventricular fibrillation (VF) and ventricular tachycardia (VT). However, nonselective alpha-receptor blocker phentolamine significantly reduced the number of premature ventricular complexes (30.5 +/- 4.5----11 +/- 3 PVC; P less than 0.05), but did not affect the frequency of occurrence of VF and VT. The above results show that alpha-adrenergic mechanisms do not play any important role in the genesis of arrhythmias during ischemia in the pig model.
Department of Physiology, Tongji Medical University, Wuhan.
A R
AR
Zou
S R
SR
Li
Y
Y
Zhang
H
H
Pei
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000188:drug therapy* / Q000209:etiology; D003327:Coronary Disease / Q000150:complications*; D004558:Electric Stimulation; D004562:Electrocardiography; D008297:Male; D013233:Stellate Ganglion; D013552:Swine
D000317:Adrenergic alpha-Antagonists