Gleason M M, Ratz P H, Flaim S F
Am J Physiol. 1985 Sep;249(3 Pt 2):H470-6. doi: 10.1152/ajpheart.1985.249.3.H470.
Calcium (Ca) influx in vascular smooth muscle is routinely measured in untethered preparations not under passive stretch, and Ca influx data are correlated with data for steady-state isometric tension obtained under parallel conditions from tethered preparations under passive stretch. The validity of this method was tested by simultaneous measurement of Ca influx and tension in tethered rings of rabbit thoracic aorta. Ca influx (45Ca 3-min pulse) and tension were measured at 3 and 30 min after norepinephrine (NE) or KCl and under control (no agonist) conditions. Active tension was significantly altered by variations in passive tension. Ca influx was unaffected by passive tension under control, NE, or KCl conditions, and results were similar at 3 and 30 min. The results confirm the validity of correlating Ca influx data from untethered rings with steady-state contractile response data obtained from tethered rings under similar experimental conditions.
血管平滑肌中的钙（Ca）内流通常在无束缚且无被动拉伸的标本中进行测量，并且Ca内流数据与在平行条件下从被动拉伸的束缚标本中获得的稳态等长张力数据相关联。通过同时测量兔胸主动脉束缚环中的Ca内流和张力来测试该方法的有效性。在去甲肾上腺素（NE）或氯化钾作用后3分钟和30分钟以及在对照（无激动剂）条件下测量Ca内流（45Ca 3分钟脉冲）和张力。主动张力因被动张力的变化而显著改变。在对照、NE或氯化钾条件下，Ca内流不受被动张力影响，且在3分钟和30分钟时结果相似。这些结果证实了将无束缚环的Ca内流数据与在类似实验条件下从束缚环获得的稳态收缩反应数据相关联的有效性。
