EFFECT OF HINDLIMB SUSPENSION ON CARDIOVASCULAR-RESPONSES TO SYMPATHOMIMETICS AND LOWER BODY NEGATIVE-PRESSURE
EFFECT OF HINDLIMB SUSPENSION ON CARDIOVASCULAR-RESPONSES TO SYMPATHOMIMETICS AND LOWER BODY NEGATIVE-PRESSURE
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DOI：
10.1152/jappl.1990.68.1.355
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发表时间：
1990-01-01
影响因子：
3.3
通讯作者：
TIPTON, CM
中科院分区：
文献类型：
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作者：
OVERTON, JM;TIPTON, CM
为了确定后肢悬吊是否与心血管失调的发展相关，在经历以下三种处理条件之一之前和之后对雄性大鼠进行了9天的研究：1）笼对照（n = 15，CON），2）水平悬吊（n = 15，HOZ）和3）头向下悬吊（n = 18，HDS）。试验包括氯醛糖-乌拉坦麻醉期间给予下体负压，以及对清醒的未受约束动物给予分级剂量的拟交感神经药物（去甲肾上腺素、苯肾上腺素和酪胺）。HDS和HOZ均与对下体负压的膨胀反应的小幅降低相关。HOZ组，而不是HDS组，表现出增强的反射性心动过速。此外，HDS和HOZ组治疗后均表现出对苯肾上腺素的升压反应降低。这些降低与肠系膜血管阻力显著减弱的增加有关。然而，压力反射控制的心率没有改变的治疗条件。总之，这些结果表明，大鼠HDS 9天未引起通常与低重力条件诱导的心血管失调相关的血流动力学反应模式。
To determine whether hindlimb suspension is associated with the development of cardiovascular deconditioning, male rats were studied before and after undergoing one of three treatment conditions for 9 days: 1) cage control (n = 15, CON), 2) horizontal suspension (n = 15, HOZ), and 3) head-down suspension (n = 18, HDS). Testing included lower body negative pressure administered during chloralose-urethan anesthesia and graded doses of sympathomimetic agents (norepinephrine, phenylephrine, and tyramine) administered to conscious unrestrained animals. Both HDS and HOZ were associated with a small decrease in the hypotensive response to lower body negative pressure. The HOZ group, but not the HDS group, exhibited augmented reflex tachycardia. Furthermore, both HDS and HOZ groups manifested reduced pressor responses to phenylephrine after treatment. These reductions were associated with significantly attenuated increases in mesenteric vascular resistance. However, baroreflex control of heart rate was not altered by the treatment conditions. Collectively, these results indicate that 9 days of HDS in rats does not elicit hemodynamic response patterns generally associated with cardiovascular deconditioning induced by hypogravic conditions.