Sh. Carlson et al., Elevated sympathetic activity contributes to hypertension and salt sensitivity in diabetic obese Zucker rats, HYPERTENSIO, 35(1), 2000, pp. 403-408
Citations number
40
Categorie Soggetti
Cardiovascular & Respiratory Systems","Cardiovascular & Hematology Research
Zucker rats are a useful model in which to define the mechanisms that link
obesity to diabetes and associated cardiovascular disease. The present stud
y tests the hypothesis that diabetic obese (compared with nondiabetic lean)
Zucker rats are hypertensive and display a further increase in arterial pr
essure when fed a high salt diet. Male, nondiabetic lean and diabetic obese
Zucker rats were chronically instrumented with telemetry probes and fed a
basal salt diet for 3 weeks followed by exposure to a high salt diet for 11
days. On the basal diet, obese (vs lean) rats had significantly higher art
erial pressures (approximate to 13 mm Hg), and the high salt diet significa
ntly elevated mean arterial pressure (MAP) in obese (but not lean) Zucker r
ats (approximate to 12 mmHg). Blockade of the sympathetic nervous system wi
th hexamethonium caused a significantly larger decrease in MAP in obese (vs
lean) Zucker rats fed the basal diet (51 vs 33 mm Hg), but the high salt d
iet did not increase: the hexamethonium-induced reduction in arterial press
ure in obese rats. Acute blockade of angiotensin receptors with losartan re
sulted in similar decreases in MAP in both groups on either diet. Acetylcho
line-induced vasodilatory capacity of the carotid artery was significantly
less in the obese (vs lean) Zucker rats. Together these data indicate that
increased sympathetic nervous system activity and decreased vascular reacti
vity may contribute to elevated arterial pressure in type 2 diabetic, obese
Zucker rats, but the sympathetic nervous system does not appear to contrib
ute to the dietary salt-sensitive hypertension in this model.