Frisbee J C, Sylvester F A, Lombard J H
Department of Physiology, Medical College of Wisconsin, Milwaukee 53226, USA.
Microcirculation. 2000 Aug;7(4):281-9.
To determine whether the impaired relaxation of skeletal muscle arterioles of rats on high-salt diet or with reduced renal mass hypertension (RRM-HT) represents intrinsic alterations to microvessels alone, or whether extravascular influences also contribute to reduced dilator responses.
Normotensive (NT) Sprague-Dawley rats were fed low-salt (LS) or high-salt (HS) diets, and RRM-HT rats were fed HS diet for 4-6 weeks. In situ and isolated cremaster muscle first-order arterioles (1A) were examined using television microscopy, and a video micrometer was used to measure diameter changes in response to acetylcholine (ACH), cholera toxin (CT), and sodium nitroprusside (SNP).
Compared to normotensive low-salt (NT-LS) rats, responses of 1A to the agonists were reduced in normotensive high-salt (NT-HS) and RRM-HT rats. Arteriolar reactivity to the agonists in NT-LS rats aid in NT-HS rats was not different between in situ and in vitro environments. However, in RRM-HT rats, the reactivity of 1A to each agonist was greater in isolated arterioles than in in situ arterioles.
These results suggest that the impaired response of skeletal muscle arterioles to vasodilator stimuli in normotensive rats on high-salt diet primarily reflects alterations to microvessels alone, while reduced dilator responses in RRM-HT rats represent a combination of extravascular influences and intrinsic alterations to arterioles themselves.
确定高盐饮食或肾实质减少性高血压（RRM-HT）大鼠骨骼肌小动脉舒张功能受损是仅代表微血管的内在改变，还是血管外因素也导致舒张反应降低。
将正常血压（NT）的Sprague-Dawley大鼠喂以低盐（LS）或高盐（HS）饮食，将RRM-HT大鼠喂以HS饮食4-6周。使用电视显微镜检查原位和分离的提睾肌一级小动脉（1A），并使用视频测微计测量对乙酰胆碱（ACH）、霍乱毒素（CT）和硝普钠（SNP）的直径变化。
与正常血压低盐（NT-LS）大鼠相比，正常血压高盐（NT-HS）和RRM-HT大鼠的1A对激动剂的反应降低。NT-LS大鼠和NT-HS大鼠的小动脉对激动剂的反应性在原位和体外环境中无差异。然而，在RRM-HT大鼠中，分离的小动脉中1A对每种激动剂的反应性高于原位小动脉。
这些结果表明，高盐饮食的正常血压大鼠骨骼肌小动脉对血管舒张刺激的反应受损主要仅反映微血管的改变，而RRM-HT大鼠舒张反应降低代表血管外因素和小动脉自身内在改变的综合作用。
