Arrhythmias induced by changing the medium of cultured rat heart muscle cells: A model for assessment of antiarrhythmic agents

The comparative study of cardiovascular toxins utilizing a sensitive indicator of sublethal toxic injury

This study measures the inhibition of [3H]uridine uptake by smooth muscle cells to determine sublethal toxic injury by the cardiovascular toxins, allylamine, isoproterenol, and beta-aminopropionitrile. The exposure period or the concentration of toxin which inhibited 30% of [3H]uridine uptake by smooth muscle cells could be utilized as an endpoint for ranking toxicity. Cytotoxicity of the three toxins to smooth muscle cells were ranked as: allylamine greater than isoproterenol greater than beta-aminopropionitrile. Recovery of cells utilizing [3H]uridine uptake inhibition as a method for assessing comparative cytotoxicity and for screening of agents potentially injurious to vascular cells.

Protection from arrhythmias of cultured heart cells by nonsteroidal antiinflammatory drugs

The nonsteroidal antiinflammatory drugs: acetylsalicylic acid, salicylic acid, sulfinpyrazone and indomethacin were tested at 10(-10) - 10(-5) M for their effect on arrhythmias of monolayer cultures of neonatal rat heart myocytes. Arrhythmias produced by reoxygenation were prevented or significantly reduced (p less than or equal to 0.05) by either indomethacin or salicylic acid at 10(-9) M. Acetylsalicylic acid and sulfinpyrazone, while not significantly anti-arrhythmic, produced consistent numerical inhibition of arrhythmias at 10(-9) M.

Arrhythmogenicity of long-chain fatty acids for cultured rat heart myocytes

Cultures of beating rat heart myocytes were exposed for 1 h to stearic, oleic, linoleic or arachidonic acid (5 x 10(-5) M at a 2 : 1 or 6 : 1 FFA/albumin ratio) in hypoxic or normoxic medium with or without glucose. After the 1 h exposure the medium was changed again to normoxic medium without FFA but with an "equivalent" amount of albumin. The grade of arrhythmia was determined at 0.5, 1, 2, 4, 8 and 16 h after addition of the medium containing FFA. Hypoxia during FFA exposure was not required for arrhythmogenesis although linoleic and arachidonic acids were less and stearic acid was more arrhythmogenic during initial hypoxia than during initial normoxia. Glucose slowed arrhythmogenesis produced by the unsaturated FFA during hypoxia and completely reversed arrhythmogenesis by stearic acid after 16 h with most treatments. Arrhythmogenesis resulting from unsaturated FFA was minimally affected by the FFA/albumin ratios used.