Effect of chronic low potassium on K+ uptake rate in myocardium and skeletal muscle of rabbits

Abstract

Objective To evaluate the effect of chronic low potassium on K+ uptake rate in the myocardium and skeletal muscle of rabbits. Methods Thirty-two adult male rabbits, aged 12-14 weeks, weighing 2.0-2.7 kg, were randomly divided into 4 groups (n=8 each) using a random number table: normal feeding group (group N), low potassium feeding group (group L), potassium supplementation control group (group SC) and potassium supplementation experimental group (group SE). N and SC groups were given a normal diet only, and L and SE groups were fed with a low potassium diet for 15 days. Potassium chloride (KCl) 0.5 mol/L was then infused intravenously at the initial rate of 60 μmol·kg-1·min-1 in SE and SC groups. Blood samples were obtained from the central artery of the left ear every 5 min for measurement of plasma K+ concentrations. The infusion rat of KCl was then adjusted until the plasma K+ concentration reached 5.5 mmol/L and maintained at this level for 1 h, and then infusion was stopped. The total volume of KCl infused was recorded. The hearts and soleus muscle of animals were excised for determination of K+ content. K+ uptake and uptake rate were calculated. Results Compared with N group, the plasma K+ concentration, and K+ content in the myocardium and soleus muscle were significantly decreased in group L(P<0.05). Compared with SC group, the total volume of KCl infused, and K+ uptake and uptake rate in the myocardium and soleus muscle were significantly increased in group SE(P<0.05). Conclusion Chronic hypokalaemia can increase K+ uptake rate in the myocardium and skeletal muscle of rabbits. Key words: Hypokalemia; Myocardium; Muscle, skeletal