Role of sympathetic nerve activity and natriuresis in the antihypertensive actions of potassium in NaCl hypertension.
Although the precise mechanism of the antihypertensive action of potassium remains controversial, the natriuretic property of potassium is thought to play an important role. Since the renal nerves have been shown to control urinary sodium excretion, the present study was performed to clarify the role of the sympathetic nervous system in the antihypertensive effect of potassium supplements in DOCA-salt hypertensive rats and in salt-sensitive hypertensive patients. Supplements of a 0.2% or a 1% KCl were able to moderate the development of the DOCA-salt hypertension dose-dependently, in combination with natriuresis. Renal norepinephrine turnover was markedly accelerated in the DOCA-salt rats as compared with the control rats, but the potassium supplements normalized it. Eleven patients, who had taken the potassium supplement (96 mEq/day) on a high-sodium diet, showed a lesser increase in mean blood pressure with sodium loading than 12 patients who did not take the potassium supplement. With a high-sodium diet, the potassium-supplemented patients retained less sodium and showed a lesser increase of plasma volume and cardiac output, and their adrenergic nervous activity was relatively lower during the early period of salt loading. Moreover, in salt-sensitive patients the potassium supplement was more effective for preventing a rise in blood pressure with sodium loading than in non-salt-sensitive ones. These results suggest that potassium may attenuate the rise in blood pressure during the DOCA-salt treatment in the rat and during sodium loading in salt-sensitive patients, mainly as a result of inhibiting sodium retention due to increased renal sodium excretion.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D000959:Antihypertensive Agents; D003900:Desoxycorticosterone; D006801:Humans; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology*; D009318:Natriuresis; D011188:Potassium / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012965:Sodium Chloride; D013564:Sympathetic Nervous System / Q000503:physiopathology*
D000959:Antihypertensive Agents; D003900:Desoxycorticosterone; D012965:Sodium Chloride; D011188:Potassium