Attenuation by dexamethasone of endotoxin protection against ischaemia-induced ventricular arrhythmias.
Ventricular arrhythmias from a 30 min occlusion of the left coronary artery were assessed in Langendorff perfused isolated hearts removed from rats administered either saline, or endotoxin derived from Escherichia coli (2.5 mg kg-1 i.p.) given either 2, 4, 8, 24 or 48 h previously. Arrhythmia severity was markedly reduced in those hearts removed from rats administered endotoxin with a maximum protection at 8h; there was a marked reduction in the incidence of ventricular fibrillation (from 54% to 4%) and in the number of ventricular premature beats during the occlusion period (e.g. from 1165 +/- 144 to 37 +/- 19; P < 0.01). Dexamethasone (3 mg kg-1, given 1 h prior to endotoxin or saline) markedly attenuated the protection afforded by endotoxin.
Song
W
W
Department of Physiology & Pharmacology, Royal College, University of Strathclyde, Glasgow.
Furman
B L
BL
Parratt
J R
JR
D000818:Animals; D001145:Arrhythmias, Cardiac / Q000150:complications* / Q000503:physiopathology; D003907:Dexamethasone / Q000494:pharmacology*; D004594:Electrophysiology; D004926:Escherichia coli; D066298:In Vitro Techniques; D008070:Lipopolysaccharides / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D008297:Male; D017202:Myocardial Ischemia / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control; D051381:Rats; D017207:Rats, Sprague-Dawley; D017180:Tachycardia, Ventricular / Q000503:physiopathology; D014693:Ventricular Fibrillation / Q000503:physiopathology
D008070:Lipopolysaccharides; D003907:Dexamethasone