The effects of nonsteroidal anti-inflammatory drugs (NSAIDs) on the spontaneously beating isolated auricles of the rabbit heart.

The effects of NSAIDs (aspirin and indomethacin) on the isolated auricles of the rabbit heart were studied by observing the effects of these drugs on automaticity, excitability and contractility of the auricles. Aspirin (25,50,100 uM) produced concentration dependent depression in the automaticity of the SA node while indomethacin (10 uM, 25 uM) has stimulant effects and 50 uM produced depressant action. Only low concentration of indomethacin (10 uM) produced significant effect. Aspirin (25,50,100 uM) and indomethacin (50 uM) have significant depressant effects on the excitability of the auricles. Aspirin (100 uM) has suppressant effects (p < 0.05) on the normal contractility while the adrenaline stimulated contractility is not suppressed by aspirin and indomethacin significantly. The results obtained in this study with aspirin and indomethacin on chronotropicity and inotropicity of the rabbit atria have been discussed in the light of experimental work done by the workers regarding conventional antiarrhythmic drugs.