DIETARY PROTEIN & DEFECT IN VASCULAR SMOOTH MUSCLE CONTRACTILITY IN HYPERTENSION

胸主动脉取自4个月大的易中风婴儿 自发性高血压大鼠及其同龄大鼠 血压正常的Wistar Kyotos(WKY)，已维持 3个月，使用四种试验性饮食之一：标准(STD)(24% 蛋白质)、低蛋白质(LP)(19%蛋白质)、高蛋白质(HP)(32% 蛋白质)或高蛋氨酸(Met)(1.9%蛋氨酸)。这个 低浓度的氯仿产生的等长张力 去甲肾上腺素(10~(-10)、10~(-9)M)在大鼠主动脉条上的作用相似 不同实验饲料(SHRSP/日粮)下的SHRSP和 标准饮食(WKY/STD)下的WKY。其中的条带 SHRSP/STD和SHRSP/LP显著降低 大剂量去甲肾上腺素(10-8，10-7M)和钾(60)的收缩反应 Mm)，而SHRSP/Met和SHRSP/HP的条带显示 收缩反应值接近正常。脱除石灰中的钙 该介质使去甲肾上腺素引起的收缩在 SHRSP/STD条带的速度快于WKY/STD条带。 SHRSP带材中Lp的存在加速了SHRSP带材的生长速度，而 MET和惠普延缓了收缩速度的下降。这个 所有实验条对NE或K+的收缩反应 演示了由FAST和 慢速部件。快分量和慢分量的值 对去甲肾上腺素的反应以条状形式显著降低 SHRSP/STD、SHRSP/LP和SHRSP/HP WKY/STD和SHRSP/Met.福斯科林也产生了类似的松弛 在SHRSP/Diets和WKY/STD的条带中 与东北航空公司预先签约。这些实验的结果 提示：(1)主动脉收缩反应的差异 正常血压WKY和SHRSP的条带可以归因于 从本质上讲，膜泡的生物化学组成 参与钙离子转运，以及(2)与来自 SHRSP/Met和SHRSP/HP，来自SHRSP/STD和 SHRSP/LP的保留能力似乎要低得多，因此 适量释放肌肉所需的钙离子 收缩。

Thoracic aortas were isolated from 4-month-old, stroke-prone spontaneously hypertensive rats (SHRSP) and age-matched normotensive Wistar Kyotos (WKY) which had been maintained for 3 months on one of four experimental diets: standard (STD) (24% protein), low protein (LP) (19% protein), high protein (HP) (32% protein), or high methionine (Met) (1.9% methionine). The isometric tensions produced by low concentrations of norepinephrine (10-10, 10-9M) were similar in aortic strips from both SHRSP under various experimental diets (SHRSP/diet) and WKY under the standard diet (WKY/STD). The strips from SHRSP/STD and SHRSP/LP exhibited significantly reduced contractile responses to high doses of NE (10-8, 10-7M) and K+ (60 mM) while strips from SHRSP/Met and SHRSP/HP demonstrated contractile response values close to normal. Removal of Ca from the medium caused NE-induced contractions to decrease at a faster rate in strips from SHRSP/STD than in WKY/STD strips. The presence of LP in SHRSP strips accelerated the rate while Met and HP slowed the rate of decline of contraction. The contractile responses of all experimental strips to either NE or K+ demonstrated a biphasic configuration consisting of a fast and slow component. The values of both the fast and slow components in response to NE were significantly lower in strips form SHRSP/STD, SHRSP/LP and SHRSP/HP than in strips from WKY/STD and SHRSP/Met. Forskolin produced similar relaxation in strips from both SHRSP/diets and WKY/STD that were precontracted with NE. The results from these experiments indicate that (1) the differences in contractile response of aortic strips from normotensive WKY and SHRSP may be attributed essentially the the biochemical make-up of the membrane vesicles involved in Ca2+ transport and (2) in contrast to aortae from SHRSP/Met and SHRSP/HP, the aortae from SHRSP/STD and SHRSP/LP seem to have a much lower ability to retain and thus release appropriate amounts of Ca2+ required for muscle contraction.