Distension-dependent changes in noradrenaline sensitivity in small arteries from the rat.
Distension-dependent changes in noradrenaline sensitivity in small arteries from the rat.
复制标题
大鼠小动脉去甲肾上腺素敏感性的扩张依赖性变化。
DOI：
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发表时间：
1985
期刊：
影响因子：
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通讯作者：
N. Sjöblom
中科院分区：
文献类型：
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作者：
H. Nilsson;N. Sjöblom
在大鼠肠系膜上动脉200微米分支环形制剂中，评估了扩张对去甲肾上腺素和钾敏感性的影响。对去甲肾上腺素的反应，最大张力发生在比钾激活时更小的管径处。对去甲肾上腺素的敏感性随着腹胀的增加而增加，而对钾的敏感性基本保持不变。在使用高钾溶液去极化的血管中，也观察到去甲肾上腺素敏感性的扩张依赖性增加。对去甲肾上腺素的扩张依赖性敏感性在等张性收缩中的作用也进行了研究。在应用去甲肾上腺素激活后，在相同剂量下，亚最大值等渗反应略小于等长反应。这可能是由于等张收缩时敏感性降低所致。在神经源性激活时，等渗反应和等长反应之间没有差异。结果表明，血管扩张增加了体外抗血管的去甲肾上腺素敏感性，但对其作为神经效应器的功能的影响可能很小。
The effects of distension on the sensitivity to noradrenaline and potassium were assessed in ring preparations of 200 micron branches from the superior mesenteric artery of the rat. In response to noradrenaline, maximal tension development occurred at smaller luminal diameters than with potassium activation. The sensitivity to noradrenaline increased with increasing distension whereas potassium sensitivity remained largely unchanged. A distension-dependent increase in noradrenaline sensitivity was observed also in vessels depolarized with high-potassium solution. The role of the distension-dependent sensitivity to noradrenaline for isotonic contractions was also studied. Upon activation with applied noradrenaline, submaximal isotonic responses were somewhat smaller than isometric responses at the same dose. This may be ascribed to a reduction in sensitivity during the isotonic contraction. Upon neurogenic activation, no difference between isotonic and isometric responses was found. The results show that distension increases noradrenaline sensitivity in resistance vessels in vitro, but that the consequences for their function as neuroeffectors may be small.