Chronic central potassium infusion prevents deoxycorticosterone-salt hypertension in rats.
Although it has long been established that cerebrospinal fluid potassium concentration (CSF [K]) is very tightly regulated, it has been reported that rats made hypertensive by central infusions of aldosterone have significantly lower CSF [K] compared with normotensive controls. We investigated whether reduced CSF [K] is also present in another animal model of hypertension, the deoxycorticosterone acetate (DOCA)-salt rat, and we hypothesized that chronic intracerebroventricular (IVT) infusion of potassium with miniosmotic pumps might attenuate the rise in blood pressure observed in these rats. DOCA-salt rats without IVT infusions or with control CSF infusions (0.5 microliter/h of 2.9 mM K for 2 wk) had a significantly increased systolic blood pressure and a significantly lower CSF [K] compared with their respective sham groups. In contrast, DOCA-salt rats receiving IVT infusions with elevated [K] (10, 30, or 150 mM) had significantly lower blood pressures compared with those receiving control CSF. They also did not exhibit decreased CSF [K] compared with their respective sham groups. At 10 and 150 mM K, the blood pressure rise in DOCA-salt rats was not significantly different from shams. At 30 mM K, there was a slight, but significant, increase in blood pressure in the DOCA-salt rats compared with their shams, but this rise was still much less than in DOCA-salt rats infused with 2.9 mM K. Infusions with elevated [K] had no effect on blood pressure in the sham animals. These studies suggest that altered brain potassium homeostasis may play an important role in the development of DOCA-salt hypertension.
Klarr
S A
SA
Department of Surgery, University of Michigan, Ann Arbor 48109.
Keep
R F
RF
Betz
A L
AL
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000502:physiology*; D002555:Cerebrospinal Fluid / Q000187:drug effects; D003900:Desoxycorticosterone; D006973:Hypertension / Q000139:chemically induced* / Q000517:prevention & control*; D007276:Injections, Intraventricular; D008297:Male; D011188:Potassium / Q000008:administration & dosage* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride; D013997:Time Factors
D003900:Desoxycorticosterone; D012965:Sodium Chloride; D011188:Potassium