Reactivity and sensitivity of the mesenteric artery in adult spontaneously hypertensive rats after chronic treatment with indapamide.
The effects of chronic treatment with indapamide (3 mg/kg/day) on the structure and function of the mesenteric artery were studied in two groups of spontaneously hypertensive rats (SHRs) using an experimental model of in situ localized mesenteric artery. Indapamide (n = 12) or placebo (n = 12) were given to 8-week-old rats for 4 weeks. After anesthesia and laparotomy, a segment of mesenteric artery (external diameter, 300-400 microns) was exposed for video-microscopic measurements. The diameter-pressure relationships were established under active conditions (phenylephrine, 10(-6) M) and passive conditions (potassium cyanide, KCN) for transmural pressure ranging from atmospheric pressure to 200 mm Hg. These studied arterial segments were then fixed and their wall cross-sectional areas (CSA) measured in transverse sections. Active wall stress and tension were defined as the differences in wall stresses and wall tensions calculated for active and passive conditions. Systolic arterial pressure and mesenteric CSA were decreased in treated rats (197 +/- 15 mm Hg vs. 211 +/- 12 mm Hg, p < 0.05; 16,230 +/- 1048 microns2 vs. 19,033 +/- 1082 microns2, p < 0.05). In both groups, mesenteric diameters were smaller under active than under passive conditions without significant differences in treated vs. untreated group under active conditions. The active wall tension was lower in treated (0.4 +/- 0.19 N/m) than in untreated rats (1.19 +/- 0.62 N/m, p < 0.05). However, there were no differences in active wall stress in both groups (103 +/- 47 kPa and 134 +/- 30 kPa).(ABSTRACT TRUNCATED AT 250 WORDS)
Zhou
H Y
HY
INSERM U141, Hôpital Lariboisière, Paris.
Schatz
C
C
Guez
D
D
Lévy
B I
BI
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006973:Hypertension / Q000473:pathology* / Q000503:physiopathology; D007190:Indapamide / Q000008:administration & dosage / Q000494:pharmacology*; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology; D010656:Phenylephrine / Q000494:pharmacology; D011312:Pressure; D051381:Rats; D011918:Rats, Inbred SHR
D010656:Phenylephrine; D007190:Indapamide