Myogenic response and wall mechanics of arterioles.
Myogenic response and wall mechanics of arterioles.
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小动脉的肌源性反应和壁力学。
DOI：
10.1152/ajpheart.1989.257.4.h1147
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Duling,BR
中科院分区：
文献类型：
--
作者：
Jackson,PA;Duling,BR
在仓鼠颊囊的孤立插管血管中评估了小动脉对腔内压力改变的反应幅度。在各种水平的平滑肌激活过程中研究了微血管，无论是自发发生的，还是由外源性激动剂包括钾（35或70 mM）和苯丙氨酸（1.25或2.50 x 10（-6）M）的应用引起的。直径-压力曲线是通过以3分钟的间隔将管腔内压力从60 mmHg降低到0 mmHg而获得的。在40 mmHg的腔内压力下，自发张力产生最大直径的34 +/- 2%的平均收缩。压力的逐步降低通常导致肌肉激活水平的降低，这导致在显著的压力范围内的净扩张。这种“肌源性反应”在调节自发性张力方面比调节外源性张力更有效。事实上，数据表明，腔内压力降低到零可以导致自发性紧张的完全失活。然而，当由外源性激动剂诱导收缩时，未观察到完全失活。小动脉中肌源性反应的幅度与自身调节的作用一致，这是先前报道的小动脉的2.5倍。数据表明，在次最大激活血管的力学分析中，必须考虑两种现象：最大激活条件下确定的经典应力-长度行为，以及由应力或长度依赖性过程引起的激活水平的叠加修改。此外，研究结果表明，当音调是自发的情况下，当音调是由外源性激动剂引起的反应有很大的差异。
The magnitude of the arteriolar response to altered intraluminal pressure was assessed in isolated, cannulated vessels of the hamster cheek pouch. Microvessels were studied during various levels of smooth muscle activation, either occurring spontaneously, or resulting from the application of exogenous agonists including potassium (35 or 70 mM) and phenylephrine (1.25 or 2.50 x 10(-6) M). Diameter-pressure curves were obtained by lowering intraluminal pressure from 60 to 0 mmHg in seven steps at 3-min intervals. At an intraluminal pressure of 40 mmHg, spontaneous tone produced an average constriction to 34 +/- 2% of the maximum diameter. Step reductions in pressure typically led to reductions in the level of activation of the muscle, which resulted in a net dilation over a significant pressure range. This “myogenic response” was more effective in modifying spontaneous tone than in modifying exogenous tone. In fact, the data suggest that reduction of the intraluminal pressure to zero can result in complete inactivation of spontaneous tone. Complete inactivation was not observed when contractions were induced by exogenous agonists, however. The magnitude of the myogenic response in arterioles was consistent with a role in autoregulation, which is 2.5-fold greater than that previously reported for small arteries. The data demonstrate that in the analysis of the mechanics of submaximally activated blood vessels one must include considerations of two phenomenon: the classical stress-length behavior as determined under conditions of maximal activation, and a superimposed modification of the activation level induced by stress- or length-dependent processes. Furthermore, the findings indicate substantial differences in response when tone is spontaneous compared with the case when tone is induced by exogenous agonists.