Regional blood flow in Dahl-Iwai salt-sensitive rats and the effects of dietary L-arginine supplementation.
The purpose of the present study was to determine 1) whether different organs undergo similar increase in vascular resistance in Dahl-Iwai salt-sensitive (S) rats, and 2) the effects of chronic oral L-arginine supplementation on the regional hemodynamics in S rats. Male 6-wk-old S rats and salt-resistant (R) rats were maintained on an 8% NaCl chow for 4 wk. One group (S or R rats) was maintained on tap water and the other group (S/Arg or R/Arg rats) received tap water containing L-arginine at a concentration of 1.5%. Organ blood flow and cardiac output were measured with microspheres in the conscious condition. Mean blood pressure in S, S/Arg, R, and R/Arg rats was 159 +/- 5, 138 +/- 3, 111 +/- 4, and 112 +/- 4 mmHg, respectively. Urinary excretion of protein and albumin in S/Arg rats was significantly suppressed compared with S rats. Concerning regional hemodynamics, the flow rate of the kidney was lower in S rats than in R rats, but there were no differences between S and R rats in the flow rates of the brain, heart, lung, liver, spleen, intestine, skeletal muscle, and skin. Thus the renal blood flow was solely reduced in S rats on a high-salt diet. The flow rate of the kidney in S/Arg rats was maintained at a higher level compared with that of S rats. L-Arginine treatment tended to produce a recovery in the urinary excretion of guanosine 3',5'-cyclic monophosphate in S rats, but had no effect in R rats. Thus the supplementation of L-arginine prevented the increase in blood pressure in S rats on a high-salt diet and normalized the abnormality of renal hemodynamics accompanying salt-induced hypertension.
Tomohiro
A
A
Department of Pharmacology, Kagawa Medical School, Japan.
Kimura
S
S
He
H
H
Fujisawa
Y
Y
Nishiyama
A
A
Kiyomoto
K
K
Aki
Y
Y
Tamaki
T
T
Abe
Y
Y
D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D001794:Blood Pressure; D001921:Brain / Q000098:blood supply; D002302:Cardiac Output; D003326:Coronary Circulation; D005527:Food, Fortified; D006339:Heart Rate; D006439:Hemodynamics; D007421:Intestine, Small / Q000098:blood supply; D007668:Kidney / Q000098:blood supply; D008099:Liver / Q000098:blood supply; D008297:Male; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains; D012039:Regional Blood Flow / Q000187:drug effects*; D012982:Sodium, Dietary / Q000494:pharmacology; D013045:Species Specificity; D013737:Testis / Q000098:blood supply; D014655:Vascular Resistance
D012982:Sodium, Dietary; D001120:Arginine