Contribution of the sympathetic nervous system to salt-sensitivity in lifetime captopril-treated spontaneously hypertensive rats.
OBJECTIVE
To test the hypothesis that, in lifetime captopril-treated spontaneously hypertensive rats (SHR), the sympathetic nervous system contributes importantly to the hypertensive effect of dietary sodium chloride supplementation.


METHODS
Male SHR (aged 6 weeks) that had been treated from conception onward with either captopril or vehicle remained on a basal sodium chloride diet or were fed a high sodium chloride diet. After 2 weeks, the rats were subjected to ganglionic blockade and 2 days later, an infusion of clonidine.


RESULTS
Lifetime captopril treatment significantly lowered mean arterial pressure in both groups. Intravenous infusion of the ganglionic blocker hexamethonium resulted in a rapid decline in MAP that eliminated the dietary sodium chloride-induced increase in MAP in both groups. Infusion of the central nervous system alpha2-adrenergic receptor agonist clonidine also resulted in a greater reduction in MAP in both groups of SHR that were fed the high (compared with the basal) sodium chloride diet.


CONCLUSIONS
In both lifetime captopril-treated and control SHR, the sympathetic nervous system contributes to the pressor effects of a high sodium chloride diet.
Wyss
J M
JM
Department of Cell Biology, University of Alabama at Birmingham, 35294-0019, USA.
Mozaffari
M S
MS
Roysommuti
S
S
D000818:Animals; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000627:therapeutic use*; D003000:Clonidine / Q000494:pharmacology; D018738:Hexamethonium / Q000627:therapeutic use; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D017673:Sodium Chloride, Dietary / Q000009:adverse effects*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000503:physiopathology*; D013565:Sympatholytics / Q000494:pharmacology
D000959:Antihypertensive Agents; D017673:Sodium Chloride, Dietary; D013565:Sympatholytics; D018738:Hexamethonium; D002216:Captopril; D003000:Clonidine