Aging and Endothelial Function of Muscle Arterioles

描述：(来自应用的逐字)骨骼肌灌注和 内皮介导的骨骼肌阻力血管系统的血管扩张 似乎随着年龄的增长而减少；然而，准确的机制 增龄性骨骼血管扩张功能减退的潜在原因 肌肉血管系统尚不清楚。我们最近的工作记录了 比目鱼肌和腓肠肌的1A小动脉血流诱导的血管扩张 老年Fischer 344大鼠的肌肉。虽然血流诱导的血管扩张 众所周知，骨骼肌小动脉是一种内皮依赖性反应， 这种反应的机制还没有在小动脉中明确。 运动肌，如比目鱼肌和腓肠肌； 此外，衰老引起的脑功能损害的机制 目前尚不清楚他们的反应。因此，我们建议调查其贡献 血管内皮依赖性血管扩张通路对血流诱导的血管扩张的影响 青年和老年Fisher 344大鼠的比目鱼肌和胃肌肌小动脉。 我们将检验这样一种假设，即衰老导致的心流障碍 这些阻力小动脉的血管扩张主要是由于血管减少。 内皮细胞产生前列腺素类血管扩张剂的能力。我们会 使用关键酶的特定抑制剂来确定黄连中的哪种成分(S) 血流诱导的血管扩张，即内皮细胞一氧化氮(NO)、前列腺素 血管扩张剂，或内皮衍生超极化因子(EDEHF)，是 老年动物的微动脉表达下调(目标1)。我们将确定是否 组织形式的蛋白质和mRNA表达减少 环氧合酶(COX-1)和内皮型一氧化氮合酶(EcNOS) NO和前列腺素类血管扩张剂的产生减少是由于 老年大鼠小动脉内流量(AIM2)。最后，因为一种增加的趋势 随着年龄的增长和锻炼，会出现更多的久坐行为 训练已被证明可以改善血管内皮依赖性的血管扩张。 骨骼肌血管系统，我们建议确定是否运动训练 可以改善骨骼组织中受损的血流诱导的血管扩张 老年大鼠的肌小动脉(目标3)。尽管老龄化已被记录在案 减少骨骼肌血管扩张反应，这些研究将是第一次 评价血管舒张性丧失的内皮机制 功能。此外，这些研究将确定运动训练是否 可以对抗衰老相关的内皮依赖性血管扩张功能的丧失 骨骼肌阻力小动脉的反应。

DESCRIPTION: (Verbatim from application) Skeletal muscle perfusion and endothelium-mediated vasodilation of the skeletal muscle resistance vasculature appear to diminish with advancing age; however, the precise mechanisms that underlie aging-induced decrements in vasodilatory function of the skeletal muscle vasculature are unclear. Our recent work has documented impaired flow-induced vasodilation in 1A arterioles from soleus and gastrocnemius muscles of aged Fischer 344 rats. Although flow-induced vasodilation of skeletal muscle arterioles is known to be an endothelium-dependent response, the mechanisms of the response have not been defined in arterioles from locomotory muscles, such as the soleus and gastrocnemius muscles, and furthermore, the mechanisms which underlie the aging-induced impairment of this response are not known. Therefore, we propose to investigate the contribution of endothelium-dependent vasodilatory pathways to flow-induced vasodilation in soleus and gastronemius muscle arterioles from young and aged Fisher 344 rats. We will test the hypothesis that the aging-induced impairment of flow-induced vasodilation in these resistance arterioles occurs primarily due to a decrease in the ability of the endothelium to produce prostanoid vasodilators. We will use specific inhibitors of key enzymes to determine which component(s) of the flow-induced vasodilation, i.e., endothelial nitric oxide (NO), prostanoid vasodilators, or endothelium-derived hyperpolarizing factor (EDEHF), is downregulated in arterioles from old animals (Aim 1). We will determine whether decreases in protein and mRNA expression for the constitutive form of cyclooxygenase (COX-1) and endothelial nitric synthase (ecNOS) potentially underlie reduced production of No and prostanoid vasodilators in response to flow in arterioles from old rats (Aim2). Finally, because an increased tendency toward more sedentary behavior occurs with advancing age and because exercise training has been shown to improve endothelium-dependent vasodilation of the skeletal muscle vasculature, we propose to determine whether exercise training can ameliorate the impaired flow-induced vasodilation that occurs in skeletal muscle arterioles from aged rats (Aim 3). Although aging has been documented to reduce skeletal muscle vasodilatory responses, these studies will be the first to evaluate the endothelial mechanisms responsible for the loss of vasodilatory function. Furthermore, these studies will determine whether exercise training can counter the aging-associated loss of endothelium-dependent vasodilatory responses in skeletal muscle resistance arterioles.