The failure of increased serum potassium to enhance the pressor response to infused calcium in normotensive men.
We evaluated the effects of an increased serum potassium level, the result of a potassium infusion, on the pressor response to infused calcium in normotensive men. Potassium infusion (0.38 mmol/kg per h for 2 h) increased serum potassium by 1.1 mmol/l with no changes in blood pressure, cardiac output or total peripheral vascular resistance (n = 6). Calcium infusion (0.19 mmol/kg per h for 1 h) and combined infusion of potassium followed by calcium increased serum calcium by 1.1 mmol/l with an elevated blood pressure, vascular resistance and no change in cardiac output (n = 8). The absolute and per cent increases in blood pressure and vascular resistance during the calcium infusion did not differ in the absence compared with in the presence of an increased serum potassium. These results indicate that a small increase in serum potassium did not modify the pressor response to infused calcium. We conclude that hypercalcaemia-induced hypertension is caused by direct effects of calcium on arterial smooth muscle.
Aoki
K
K
Second Department of Internal Medicine, Nagoya City University Medical School, Japan.
Suzuki
T
T
D000328:Adult; D001794:Blood Pressure / Q000187:drug effects* / Q000502:physiology; D002118:Calcium / Q000494:pharmacology*; D002302:Cardiac Output / Q000187:drug effects; D006801:Humans; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D011188:Potassium / Q000097:blood* / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects
D011188:Potassium; D002118:Calcium