The effects of ethanol and lead, alone and in combination, on the severity of arrhythmias induced by coronary artery occlusion, and by noradrenaline, in anaesthetised rats

Abstract

The aim of this study was to investigate whether chronic (3 or 10 months) administration, via the drinking water, of lead (25 ppm) and/or ethanol (25% v/v) altered the susceptibility of the heart to arrhythmias induced either by coronary artery occlusion or noradrenaline infusion in pentobarbitone-anaesthetised male Sprague-Dawley rats. The cardiac effects of acute intravenous infusions of ethanol (17, 33 and 66 mg kg-1 min-1) were also measured. Chronic exposure to ethanol and/or lead in the drinking water had no marked effect on the severity of arrhythmias occurring within the initial 30 min of coronary artery occlusion. In control rats and in those administered ethanol and/or lead for 10 months, noradrenaline (16 micrograms kg-1 min-1 given IV 1 h post-occlusion for a 15-min period) induced a similar number of ectopic beats during the infusion period, although these arrhythmias persisted beyond the infusion period in treated animals only. There was a significant accumulation of lead in the bone but not in the blood of lead-treated rats. Blood ethanol concentrations varied considerably between animals, ranging from 0 to 319 mg %. Ethanol (66 mg kg-1 min-1) given acutely and yielding a blood concentration of 174 mg % had a slight antiarrhythmic effect in this model.