Belik J
Department of Pediatrics, University of Manitoba, Winnipeg, Canada.
Pediatr Res. 1994 Jul;36(1 Pt 1):34-40. doi: 10.1203/00006450-199407001-00006.
To evaluate the myogenic response and its ontogeny in large pulmonary arteries, we studied 45 newborn and 30 adult guinea pigs. Compared with the those of the adult, the newborn arterial vessels possessed a significantly (p < 0.01) smaller diameter (1153 +/- 34 versus 1656 +/- 65 microns), static compliance (2.2 +/- 0.3 versus 4.6 +/- 0.7 microns/mN), and active stress (3.4 +/- 0.4 versus 5.8 +/- 0.7 mN/mm2). Stretch-induced contraction was obtained by quick stretch of the vessel segments to 120, 140, 160, 180, or 200% of their optimal length, and the myogenic response was measured as the change in force after muscle relaxation with papaverine. A myogenic response was observed in 94% of the newborn and 93% of adult vessel segments, and significant age differences in the response were present. The magnitude of the active force generated for any stretch over 120% was significantly greater in the newborn (p < 0.01), and as a percentage of K+ (127 mM) stimulation, a 2-fold stretch of the vessels' optimal length resulted in a force of 1073 +/- 159% in the newborn compared with 51 +/- 16% in the adult (p < 0.01). The myogenic response in these large pulmonary vessels was completely suppressed by a calcium channel blocker (D-600) but unaltered by addition of a nitric oxide synthase inhibitor (NG-methyl-L-arginine) or indomethacin. We conclude that the large pulmonary arterial vessels of the guinea pig exhibit a powerful stretch-induced myogenic response that is greater in the newborn period.(ABSTRACT TRUNCATED AT 250 WORDS)
为了评估大肺动脉的肌源性反应及其个体发育情况，我们研究了45只新生豚鼠和30只成年豚鼠。与成年豚鼠相比，新生豚鼠的动脉血管直径显著更小（p < 0.01）（分别为1153 ± 34微米和1656 ± 65微米），静态顺应性更低（分别为2.2 ± 0.3和4.6 ± 0.7微米/毫牛顿），主动应力也更低（分别为3.4 ± 0.4和5.8 ± 0.7毫牛顿/平方毫米）。通过将血管段快速拉伸至其最佳长度的120%、140%、160%、180%或200%来获得拉伸诱导的收缩，并使用罂粟碱使肌肉松弛后，将肌源性反应测量为力的变化。在94%的新生血管段和93%的成年血管段中观察到了肌源性反应，且反应存在显著的年龄差异。在新生豚鼠中，任何超过120%拉伸产生的主动力大小显著更大（p < 0.01），作为K +（127 mM）刺激的百分比，血管最佳长度2倍的拉伸在新生豚鼠中产生的力为1073 ± 159%，而在成年豚鼠中为51 ± 16%（p < 0.01）。这些大肺动脉中的肌源性反应被钙通道阻滞剂（D - 600）完全抑制，但添加一氧化氮合酶抑制剂（NG - 甲基 - L - 精氨酸）或吲哚美辛后未改变。我们得出结论，豚鼠的大肺动脉血管表现出强大的拉伸诱导肌源性反应，在新生期更大。（摘要截断于250字）
