Article

Augmented adrenergic vasoconstriction in hypertensive diabetic obese Zucker rats.

Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
AJP Heart and Circulatory Physiology (impact factor: 3.71). 04/2002; 282(3):H816-20. DOI:10.1152/ajpheart.00695.2001 pp.H816-20
Source: PubMed

ABSTRACT This study examined skeletal muscle microvessel reactivity to constrictor stimuli in obese (OZR) versus lean Zucker rats (LZR). Gracilis arteries from both rat groups were isolated, cannulated with glass micropipettes, and viewed via television microscopy. Changes in vessel diameter were measured with a video micrometer. Arterial constriction to norepinephrine was elevated in OZR versus LZR, although vasoconstrictor reactivity to endothelin and angiotensin II was unaltered. Differences in reactivity between vessels of LZR and OZR were not explained by the loss of either endothelial nitric oxide synthase or beta-adrenergic receptor function. Reactivity of in situ cremasteric arterioles of OZR to norepinephrine was elevated versus LZR. Treatment with prazosin increased the diameter of in vivo gracilis arteries of OZR to levels determined in LZR and also normalized blood pressure in OZR. These results suggest that the constrictor reactivity of skeletal muscle microvessels in OZR is heightened in response to alpha-adrenergic stimuli and that development of diabetes in OZR may be associated with impaired skeletal muscle perfusion and hypertension due to microvessel hyperreactivity in response to sympathetic stimulation.

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Keywords

alpha-adrenergic stimuli
 
angiotensin II
 
Arterial constriction
 
beta-adrenergic receptor function
 
constrictor reactivity
 
constrictor stimuli
 
endothelial nitric oxide synthase
 
glass micropipettes
 
Gracilis arteries
 
lean Zucker rats
 
microvessel hyperreactivity
 
normalized blood pressure
 
rat groups
 
situ cremasteric arterioles
 
skeletal muscle microvessel reactivity
 
skeletal muscle microvessels
 
skeletal muscle perfusion
 
sympathetic stimulation
 
vasoconstrictor reactivity
 
vivo gracilis arteries