DIETARY PROTEIN & DEFECT IN VASCULAR SMOOTH MUSCLE CONTRACTILITY IN HYPERTENSION

膳食蛋白质

• 批准号: 3942896
• 负责人: M DIOLULU
• 金额: --
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3942896
• 关键词: aorta; calcium metabolism; cardiovascular pharmacology; dietary proteins; hypertension; muscle contraction; norepinephrine; vascular smooth muscle

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.

从一个4个月大的，有中风倾向的 自发性高血压大鼠（SHRSP）和年龄匹配的 血压正常的Wistar Kyotos（WKY），已维持 3个月的四个实验饮食之一：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）或高甲硫氨酸（Met）（1.9%甲硫氨酸）。 的 等长张力产生的低浓度的 去甲肾上腺素（10-10，10- 9 M）在主动脉条中相似， 在各种实验饮食下的SHRSP（SHRSP/饮食）和 标准饮食下的WKY（WKY/STD）。 The Strips从 SHRSP/STD和SHRSP/LP均显著降低 高剂量NE（10 ~（-8）、10 ~（-7）M）和K ~+（60 而来自SHRSP/Met和SHRSP/HP的条带证实了 收缩反应值接近正常 去除钙 介质引起NE诱导的收缩减少， SHRSP/STD的条带比WKY/STD条带的速率快。 SHRSP条中LP的存在加速了该速率， Met和HP减缓了收缩的下降速度。 的 所有实验条对NE或K+的收缩反应 证明了一种由快速和 慢分量 快分量和慢分量的值 对NE的反应呈条带状显著降低 SHRSP/STD、SHRSP/LP和SHRSP/HP的条带中， WKY/STD和SHRSP/Met。 毛喉素产生类似的松弛 在来自SHRSP/饮食和WKY/STD的条带中， 与NE签约。 这些实验的结果 表明：（1）主动脉收缩反应的差异 正常血压WKY和SHRSP的条带可能归因于 本质上是膜囊泡的生化组成 参与Ca ~（2+）的运输;（2）与来自 SHRSP/Met和SHRSP/HP，SHRSP/STD和SHRSP/HP的代谢产物， SHRSP/LP似乎具有低得多的保持能力， 释放肌肉所需的适量Ca 2 + 收缩。