HIGH POTASSIUM INTAKE ATTENUATES ANTINATRIURETIC RESPONSE TO AIR STRESS IN DOCA-SALT RATS

We studied the effects of potassium supplementation (2 wk of 0.5% KCl to drink) on responses of renal function to a stressful environmental stimulus (air stress) in deoxycorticosterone acetate (DOCA)-salt rats. In conscious DOCA-salt rats, air stress decreased urine flow rate and urinary sodium excretion without changes in effective renal plasma flow and glomerular filtration rate, whereas in normotensive vehicle-treated rats air stress had no effect on these measures. Renal denervation abolished the antidiuretic and antinatriuretic responses to air stress in DOCA-salt rats. Correspondingly potassium supplementation in DOCA-salt rats could not only reduce basal blood pressure significantly but also attenuate the antidiuretic and antinatriuretic responses to air stress without renal denervation. Evidence suggests that the attenuation by potassium supplementation of air stress-induced decrease in urine flow and sodium excretion in DOCA-salt rats may be partly involved in the natriuretic and the resultant antihypertensive actions of potassium in DOCA-salt hypertensive rats, but the mechanisms could not be clarified by the present study.