Differential blood pressure responses to oral and central salt administration in two substrains of Dahl rats.
Studies were made on whether oral or intraventricular (icv) NaCl had different effects on the blood pressure (BP) of Dahl rats. Five groups of each strain of Dahl rats, salt-sensitive (S) and salt-resistant (R) rats, were given, respectively, a diet containing 0.3% and icv infusion of 0.15 mol/L NaCl (group 1, control group) or 0.8 mol/L NaCl (group 2), a diet containing 8% NaCl and icv infusion of 0.15 mol/L (group 3) or 0.8 mol/L NaCl (group 4) for 12 days, or an 8% NaCl diet and icv infusion of 5% glucose (group 5). The icv infusions were made into the third cerebral ventricle with an osmotic minipump. In the control group of S rats (group 1) the BP was 120 +/- 4 mm Hg, whereas the BP in groups 3, 4 and 5 were 154 +/- 4, 161 +/- 5 and 153 +/- 3 mm Hg, respectively, and that in group 2 was 142 +/- 3 mm Hg on day 12. In the R rat, group 2 and group 4 showed a significant increase in BP over that of the control group. Multivariate analysis (quantification I) of these data confirmed that the BP of S rats was more sensitive to oral salt loading and that of the R rat was more strongly influenced by central salt administration. These results indicate that the two substrains of Dahl rats show different BP responses to oral and central administrations of NaCl.
Katahira
K
K
Department of Geriatric Medicine, Osaka University Medical School, Japan.
Mikami
H
H
Otsuka
A
A
Tsunetoshi
T
T
Kohara
K
K
Ogihara
T
T
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002552:Cerebral Ventricles; D006973:Hypertension / Q000134:cerebrospinal fluid / Q000503:physiopathology*; D007260:Infusion Pumps; D015999:Multivariate Analysis; D051381:Rats; D011919:Rats, Inbred Strains; D012965:Sodium Chloride / Q000008:administration & dosage / Q000134:cerebrospinal fluid / Q000494:pharmacology*; D013045:Species Specificity
D012965:Sodium Chloride