Vasoconstrictor properties of rat aorta are diminished by hindlimb unweighting.
Vasoconstrictor properties of rat aorta are diminished by hindlimb unweighting.
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DOI：
10.1152/jappl.1993.75.6.2620
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发表时间：
1993-12
影响因子：
3.3
通讯作者：
M. Delp;T. Holder-Binkley;M. Laughlin;E. Hasser
中科院分区：
文献类型：
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作者：
M. Delp;T. Holder-Binkley;M. Laughlin;E. Hasser
人类长期卧床和暴露于失重状态会导致心血管改变，其特征是立位不耐受和运动能力下降。心血管功能的改变被认为与外周血管反应性的变化有因果关系。使用大鼠后肢减重（HU）作为动物模型，以确定负重活动的长期减少是否会引起外周动脉血管血管反应性的变化。使用离体腹主动脉和胸主动脉环在体外检查对血管活性化合物的反应。血管收缩剂KCl（10-100 mM）、去甲肾上腺素（NE; 10（-9）-10（-4）M）、苯肾上腺素（10（-9）-10（-4）M）、精氨酸加压素（10（-13）-3 x 10（-5）M）和CaCl 2（10（-6）-10（-2）M）在HU大鼠腹主动脉环中诱发的最大等长收缩张力较低。在HU动物的节段中，对KCl的敏感性[产生50%最大血管收缩反应（EC 50）的激动剂浓度]增强，但对其他收缩剂无差异。HU还可减弱KCl（10-100 mM）和NE（10（-9）-10（-4）M）对胸主动脉环的最大收缩反应。在用10（-4）M NE预收缩的腹主动脉环中，由硝普钠（10（-10）-10（-4）M）和8-溴鸟苷3 '，5'-环一磷酸（10（-6）-10（-2）M）诱导的最大血管舒张反应在HU大鼠的血管环中更大。然而，用10（-7）M NE预收缩，硝普钠（10（-10）-10（-4）M）和乙酰胆碱（10（-9）-10（-4）M）诱导的最大舒张反应在组间无差异。（250字处删节）
Prolonged bed rest and exposure to weightlessness in humans result in cardiovascular alterations that are characterized by orthostatic intolerance and decreased exercise capacity. Modifications of cardiovascular function have been suggested to be causally related to changes in peripheral vascular reactivity. Rat hindlimb unweighting (HU) was used as an animal model to determine whether prolonged decreases in weight-bearing activity induce changes in vasoreactivity of peripheral arterial vessels. Responses to vasoactive compounds were examined in vitro using isolated abdominal and thoracic aortic rings. Maximal isometric contractile tension evoked by the vasoconstrictors KCl (10-100 mM), norepinephrine (NE; 10(-9)-10(-4) M), phenylephrine (10(-9)-10(-4) M), arginine vasopressin (10(-13)-3 x 10(-5) M), and CaCl2 (10(-6)-10(-2) M) was lower in abdominal aortic rings from HU rats. Sensitivity [agonist concentration that produced 50% of maximal vasoconstrictor response (EC50)] to KCl was enhanced in segments from HU animals but was not different for the other constrictors. Maximal contractile responses of thoracic aortic rings to KCl (10-100 mM) and NE (10(-9)-10(-4) M) were also attenuated by HU. In abdominal aortic rings preconstricted with 10(-4) M NE, maximal vasodilatory responses induced by sodium nitroprusside (10(-10)-10(-4) M) and 8-bromoguanosine 3',5'-cyclic monophosphate (10(-6)-10(-2) M) were greater in vessel rings from HU rats. However, with 10(-7) M NE preconstriction, maximal dilatory responses induced by sodium nitroprusside (10(-10)-10(-4) M) and acetylcholine (10(-9)-10(-4) M) were not different between groups.(ABSTRACT TRUNCATED AT 250 WORDS)