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The effects of carbon monoxide on the heart: an in vitro study
Insights
Carbon monoxide (CO) exposure increased coronary flow in isolated rat hearts but decreased heart rate and pulse pressure. Coronary flow is the most sensitive indicator of CO toxicity in this model.
Area of Science:
- Cardiovascular Physiology
- Toxicology
Background:
- Carbon monoxide (CO) is a toxic gas with known cardiovascular effects.
- Understanding CO's impact on cardiac function is crucial for assessing its toxicity.
Purpose of the Study:
- To investigate the effects of increasing carbon monoxide concentrations on the isolated, spontaneously beating rat heart.
- To identify the most sensitive indicator of CO toxicity in cardiac function.
Main Methods:
- Isolated hearts from male Sprague Dawley rats were perfused with Krebs-Henseleit solution.
- Cardiac function (heart rate, pulse pressure) and coronary flow were measured.
- Hearts were exposed to increasing CO concentrations with decreasing oxygen levels.
Main Results:
- Coronary flow increased at CO concentrations below 50%, with a 40% increase at 10% CO.
- Heart rate and pulse pressure were generally depressed by CO exposure.
- Pulse pressure decreased significantly at 50% CO and above.
Conclusions:
- Coronary flow is the most sensitive physiological indicator of carbon monoxide toxicity in the isolated rat heart model.
- CO exerts complex effects on cardiac function, increasing flow but impairing mechanical performance at higher concentrations.
Abstract:
Experiments were conducted to assess the effects of increasing concentrations of carbon monoxide (CO) on the isolated spontaneously beating rat heart. Hearts removed from male Sprague Dawley rats were perfused via the aorta with Krebs-Henseleit solution. Coronary flow was timed and collected in a calibrated vessel. Heart rate and pulse pressure were measured by a catheter inserted in the left ventricle and attached to a pressure transducer. After 30 min, the hearts were challenged for 10 min with perfusate containing increasing concentrations of CO and decreasing concentrations of 02. Coronary flow increased in response to CO concentrations below 50%. After 8 min, coronary flow increased by 40% in response to 10% CO challenge. Heart rate and pulse pressure were generally depressed by CO. Heart rate was depressed at the end of 8 min by 5, 10, 38, and 64%, respectively, by solutions equilibrated against 10, 25, 50, and 95% CO. Pulse pressure decreased with concentrations of 50% CO and above. These results indicate that coronary flow appears to be the most sensitive indicator of CO toxicity in the isolated heart.