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Bradykinin B2 receptor
Normal development
Development of hypertension and heart failure with aging
Deficient in contractile response to bradykinin in smooth muscle preparation
Exagerated blood pressure response to high salt intake an angiotensin II
Reference
Emanueli C, Maestri R, Corradi D, Marchione R, Minasi A, Tozzi MG, Salis MB, Straino S, Capogrossi MC,
Olivetti G, Madeddu P: Dilated and failing cardiomyopathy in bradykinin B(2) receptor knockout mice. Circulation 1999 Dec 7;100(23):2359-65
ABSTRACT
Background: The activation of B(2) receptors by kinins
could exert cardioprotective effects in myocardial
ischemia and heart failure. METHODS AND RESULTS: To
test whether the absence of bradykinin B(2) receptors
may affect cardiac structure and function, we examined
the developmental changes in blood pressure (BP),
heart rate, and heart morphology of bradykinin B(2)
receptor gene knockout (B(2)(-/-)), heterozygous
(B(2)(+/-)), and wild-type (B(2)(+/+)) mice. The BP of
B(2)(-/-) mice, which was still normal at 50 days of
age, gradually increased, reaching a plateau at 6
months (136+/-3 versus 109+/-1 mm Hg in B(2)(+/+),
P<0.01). In B(2)(+/-) mice, BP elevation was delayed.
At 40 days, the heart rate was higher (P<0.01) in
B(2)(-/-) and B(2)(+/-) than in B(2)(+/+) mice,
whereas the left ventricular (LV) weight and chamber
volume were similar among groups. Thereafter, the LV
growth rate of B(2)(-/-) and B(2)(+/-) mice was
accelerated, leading at 360 days to a LV
weight-to-body weight ratio that was 9% and 17%
higher, respectively, than that of B(2)(+/+) mice. In
B(2)(-/-) mice, hypertrophy was associated with a
marked chamber dilatation (42% larger than that of
B(2)(+/+) mice), an elevation in LV end-diastolic
pressure (25+/-3 versus 5+/-1 mm Hg in B(2)(+/+) mice,
P<0.01), and reparative fibrosis. CONCLUSIONS: The
disruption of the bradykinin B(2) receptor leads to
hypertension, LV remodeling, and functional
impairment, implying that kinins are essential for the
functional and structural preservation of the heart.
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