[Antihypertensive action of K in rats with DOCA-salt-induced hypertension]

We investigated the role of renal sympathetic tone and central noradrenergic neurons in the mechanism for natriuretic and antihypertensive effects of potassium supplement in DOCA-salt hypertensive rats. Systolic blood pressure of DOCA-salt rats continued to rise during 4 weeks of DOCA-salt (1% NaCl) treatment. In contrast, 0.2% KCl or 1% KCl supplement attenuated the development of the hypertension dose-relatedly. One percent KCl supplement attenuated sodium retention and prevented the increased sodium space in DOCA-salt rats. Whereas norepinephrine turnover rate in the kidney of DOCA-salt rats after the 4-week treatment was markedly accelerated, it was normalized by 0.2% KCl or 1% KCl supplement. On the other hand, norepinephrine turnover rates in the hypothalamus and medulla oblongata of DOCA-salt rats were delayed, while they were restored by the KCl supplement. These results suggest that potassium supplement in DOCA-salt rats attenuated the development of the hypertension and that it may be attributed to the restoration of sodium retention and thereby volume expansion. It appears that the restoration of either the increased renal sympathetic tone or the decreased noradrenergic nerve activity in the brain-stem may be involved in the natriuretic and antihypertensive effects of potassium supplements in DOCA-salt hypertensive rats.