Lin H, McGrath J J
Department of Physiology, Texas Tech University Health Sciences Center, Lubbock 79430.
Life Sci. 1988;43(22):1813-6. doi: 10.1016/0024-3205(88)90280-9.
Previously we showed that carbon monoxide (CO) relaxes vascular smooth muscle in the working heart and thoracic aorta preparations perfused with hemoglobin-free, Krebs-Henseleit (KH) solution. The CO-induced relaxation was not caused by hypoxia, nor was it mediated by adrenergic influences, adenosine, or prostaglandins. In these studies the effect of CO on calcium (Ca++) concentrations in vascular smooth muscle was determined using 45Ca as a tracer. Isolated rat thoracic aorta segments were incubated with 45Ca and gassed with O2, N2, or CO for 60 min. Verapamil was used to verify the effectiveness of the test system. Ca++ concentrations were 488 +/- 35 and 515 +/- 26 mM/g tissue (X +/- SE) in aortic rings gassed with O2 and N2, respectively. CO reduced Ca++ concentrations significantly (P less than 0.01) by 29% to 369 +/- 18 mM/g tissue. Verapamil treatment reduced Ca++ concentrations by 40% to 314 +/- 23 mM/g tissue. These results suggest that CO relaxes vascular smooth muscle and dilates blood vessels by decreasing Ca++ concentrations in vascular smooth muscle.
此前我们发现，在灌注无血红蛋白的克雷布斯 - 亨泽莱特（KH）溶液的工作心脏和胸主动脉标本中，一氧化碳（CO）可使血管平滑肌舒张。CO诱导的舒张并非由缺氧引起，也不是由肾上腺素能影响、腺苷或前列腺素介导的。在这些研究中，以45Ca作为示踪剂测定了CO对血管平滑肌中钙（Ca++）浓度的影响。将分离的大鼠胸主动脉段与45Ca一起孵育，并分别用O2、N2或CO通气60分钟。使用维拉帕米来验证测试系统的有效性。用O2和N2通气的主动脉环中，Ca++浓度分别为488±35和515±26 mM/g组织（X±SE）。CO使Ca++浓度显著降低（P<0.01）29%，降至369±18 mM/g组织。维拉帕米处理使Ca++浓度降低40%，降至314±23 mM/g组织。这些结果表明，CO通过降低血管平滑肌中的Ca++浓度来使血管平滑肌舒张并扩张血管。
