Effect of Hypercapnia on Myocardial Potassium Movement in the Dog
This investigation tested the hypothesis that uptake of potassium during respiratory acidosis is secondary to the increased catecholamine activity which accompanies hypercapnia. The plasma K+ concentration of simultaneously drawn arterial and coronary sinus blood samples from dogs was determined under three conditions: (1) hypercapnia (25% CO2-75% O2), (2) normocapnia (25% N2-75% O2) + propranolol (a beta-receptor blocker), and (3) hypercapnia + propranolol. The change during hypercapnia from uptake of K+ to loss of K+ after administration of propranolol (0.05 mg/kg, iv) was statistically significant. However, the administration of propranolol during normocapnia had no effect on myocardial K+ movement. Changes in heart rate and myocardial contractility did not explain the change in myocardial K+ movement during hypercapnia following the administration of propranolol. These data suggest that uptake of K+ is secondary to the increased catecholamine activity which accompanies hypercapnia.
- Received August 13, 1971.
- Accepted March 8, 1972.
- © 1972 American Heart Association, Inc.