Effect of age on cardiovascular responses to static muscular contraction in beagles.
Effect of age on cardiovascular responses to static muscular contraction in beagles.
复制标题
年龄对比格犬静态肌肉收缩心血管反应的影响。
DOI：
10.1152/jappl.1992.73.6.2320
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Haidet,GC
中科院分区：
文献类型：
--
作者：
Haidet,GC
在麻醉动物中诱导的肌肉收缩导致显著的血液动力学和局部血流量（RBF）变化。虽然收缩肌肉引起的反射性心血管反应已被牢固确立，但对年龄对这些反应的影响知之甚少。由于涉及交感神经激活的其他反射反应似乎随着年龄的增长而减弱，因此假设通常在肌肉收缩期间发生的反射传出心血管反应在衰老犬中会受损。因此，在α-氯醛糖麻醉期间，在8至14岁和2至3岁比格犬中评价了诱导静态后肢收缩（HLC）的血流动力学和RBF反应。两组的大部分血流动力学参数基本相似，但老年犬的心率显著高于老年犬（P < 0.05）。在HLC期间，年轻和老年犬的心率和血压增加。然而，老年犬的每搏输出量和心输出量增加更大，同时在年轻犬中未观察到全身血管阻力降低。在八个腹部区域循环中的六个和四个骨骼肌组中的每一个中，没有观察到基线RBF（微球）的年龄相关差异。在HLC期间，年轻和年老的狗的8个腹部器官中有6个发生RBF减少。然而，年轻犬与老年犬相比，所有8个腹部区域的RBF降低和伴随的血管阻力增加几乎是老年犬的两倍。在非收缩骨骼肌中，年轻犬的RBF下降，血管阻力增加了4倍。（250字处删节）
Induced muscular contraction in anesthetized animals results in significant hemodynamic and regional blood flow (RBF) changes. Although reflex cardiovascular responses initiated in contracting muscle have been firmly established, little is known about the effects of age on these responses. Because other reflex responses that involve sympathetic activation appear to be attenuated with age, it was hypothesized that reflex efferent cardiovascular responses that normally occur during muscular contraction would be impaired in senescent dogs. Therefore, hemodynamic and RBF responses to induced static hindlimb contraction (HLC) were evaluated in 8- to 14- and 2- to 3-yr-old beagles during alpha-chloralose anesthesia. Most baseline hemodynamic parameters were similar in both groups, but heart rate was significantly (P < 0.05) higher in old dogs. During HLC, heart rate and blood pressure increased in the young and old dogs. However, increases in stroke volume and cardiac output were greater in old dogs, combined with a reduction in systemic vascular resistance not observed in young dogs. No age-related difference in baseline RBF (microspheres) was observed in six of eight abdominal regional circulations and in each of four skeletal muscle groups. During HLC, RBF reductions occurred in six of eight abdominal organs in young and old dogs. However, the reduction in RBF and concomitant increase in vascular resistance in all eight abdominal regions combined was almost twice as great in young vs. old dogs. In noncontracting skeletal muscle, RBF decreased and vascular resistance increased four times more in young vs. old dogs.(ABSTRACT TRUNCATED AT 250 WORDS)