Indapamide improves flow-induced dilation in hypertensive rats with a high salt intake.
OBJECTIVE
Spontaneously hypertensive rats (SHR) are sensitive to a high salt intake and we investigated the question of whether flow-induced dilation is affected by this type of diet, as flow responses are especially sensitive to small changes in extracellular sodium concentrations.


METHODS
We evaluated the effects of a diuretic (indapamide, 1.5 mg/kg per day, 8 weeks) on four groups of SHR (n=42). One group was fed with a normal-salt diet (0.4%, control group, n=10), the second with a high-sodium diet (8%, n=12), the third with a high-sodium diet and indapamide (1.5 mg/kg per day, 8% salt, n=10) and the fourth group was fed with indapamide alone (1.5 mg/kg per day, n=10). The response to flow was studied in mesenteric resistance arteries (146+/-6.1 microm internal diameter, pressure 100 mmHg) cannulated in vitro in an arteriograph.


RESULTS
The increase in mean arterial pressure (from 186+/-4 to 218+/-6 mmHg; P < 0.01) and heart weight: body weight ratio (3.48+/-0.09 versus 4.34+/-0.1 mg/g; P< 0.01) caused by the high salt intake was prevented by indapamide. A high salt intake significantly decreased flow-induced dilation (6+/-0.8 versus 10.7+/-1.2 microm dilation with a flow of 160 microl/min; P< 0.05), while indapamide significantly prevented the decrease in flow-induced dilation in high-salt SHR. Indapamide had no significant effect on flow-induced dilation in mesenteric resistance arteries from SHR with a normal-salt diet.


CONCLUSIONS
Indapamide prevented the decrease in flow-induced dilation caused by a high-salt diet Therefore, indapamide might counteract the disturbance in sodium-sensitive flow sensor(s), through a diuretic effect.
Matrougui
K
K
INSERM U141, IFR 6 (Circulation Lariboisière), Université Paris VII, France.
Lévy
B I
BI
Schiavi
P
P
Guez
D
D
Henrion
D
D
D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D004232:Diuretics / Q000627:therapeutic use*; D005110:Extracellular Space / Q000378:metabolism; D006973:Hypertension / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology*; D007190:Indapamide / Q000627:therapeutic use*; D008638:Mesenteric Arteries / Q000187:drug effects / Q000503:physiopathology; D051381:Rats; D011918:Rats, Inbred SHR; D012964:Sodium / Q000378:metabolism; D017673:Sodium Chloride, Dietary / Q000009:adverse effects*; D016896:Treatment Outcome; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects*
D004232:Diuretics; D017673:Sodium Chloride, Dietary; D012964:Sodium; D007190:Indapamide