Effects of hypoxia on myocardial digoxin uptake and levels of plasma catecholamines in anaesthetised dogs.
The effect of hypoxia on digoxin pharmacokinetics, myocardial digoxin uptake and levels of plasma catecholamines in dogs was studied to clarify the mechanism of enhanced sensitivity to digitalis in hypoxia. Sixteen mongrel dogs were anaesthetised and artificially respired; eight with room air, eight with 8% oxygen in nitrogen, and digoxin (0.05 mg . kg-1) was intravenously given to each dog. There was no difference between hypoxic and non-hypoxic dogs in pharmacokinetic curves of digoxin. The level of myocardial digoxin in hypoxic dogs was significantly lower than that in non-hypoxic dogs. The level of plasma adrenaline in hypoxic dogs was significantly higher than that in non-hypoxic dogs (P less than 0.01). These data suggest that enhanced sensitivity to digoxin in hypoxia may be attributable not to abnormal digoxin pharmacokinetics or increased myocardial digoxin uptake but partly to higher levels of plasma catecholamines.
D000818:Animals; D004077:Digoxin / Q000378:metabolism*; D004285:Dogs; D004837:Epinephrine / Q000097:blood; D000860:Hypoxia / Q000378:metabolism*; D007700:Kinetics; D009206:Myocardium / Q000378:metabolism*; D009638:Norepinephrine / Q000097:blood
D004077:Digoxin; D009638:Norepinephrine; D004837:Epinephrine