Preventive dietary potassium supplementation attenuated the development of severe salt hypertension in young Dahl rats by decreasing sympathetic vasoconstriction, but had no effect in adult rats.
Does dietary potassium supplementation attenuate the development of salt hypertension in young and adult salt-sensitive Dahl rats?
Preventive dietary potassium supplementation attenuates salt-induced hypertension in young, but not adult, salt-sensitive Dahl rats primarily by reducing sympathetic vasoconstriction.
AIM: Increased potassium intake attenuates the development of salt-dependent hypertension, but the detailed mechanisms of blood pressure (BP) reduction are still unclear. The aims of our study were (i) to elucidate these mechanisms, (ii) to compare preventive potassium effects in immature and adult animals and (iii) to evaluate the therapeutic effects of dietary potassium supplementation in rats with established salt hypertension. METHODS: Young (4-week-old) and adult (24-week-old) female salt-sensitive Dahl rats were fed a high-salt diet (5% NaCl) or a high-salt diet supplemented with 3% KCl for 5 weeks. The participation of vasoconstrictor (renin-angiotensin and sympathetic nervous systems) and vasodilator systems prostanoids, Ca(2+) -activated K(+) channels, nitric oxide (NO) was evaluated using a sequential blockade of these systems. RESULTS: Preventive potassium supplementation attenuated the development of severe salt hypertension in young rats, whereas it had no effects on BP in adult rats with moderate hypertension. Enhanced sympathetic vasoconstriction was responsible for salt hypertension in young rats and its attenuation for potassium-induced BP reduction. Conversely, neither salt hypertension nor its potassium-induced attenuation were associated with significant changes of the vasodilator systems studied. The relative deficiency of vasodilator action of NO and Ca(2+) -activated K(+) channels in salt hypertensive Dahl rats was not improved by potassium supplementation. CONCLUSIONS: The attenuation of enhanced sympathetic vasoconstriction is the principal mechanism of antihypertensive action exerted by preventive potassium supplementation in immature Dahl rats. Dietary potassium supplementation has no preventive effects on BP in adult salt-loaded animals or no therapeutic effects on established salt hypertension in young rats.
Zicha et al. (Fri,) conducted a other in Salt-dependent hypertension. Dietary potassium supplementation vs. High-salt diet (5% NaCl) alone was evaluated on Blood pressure reduction and mechanisms (sympathetic vasoconstriction, vasodilator systems). Preventive dietary potassium supplementation attenuated the development of severe salt hypertension in young Dahl rats by decreasing sympathetic vasoconstriction, but had no effect in adult rats.