Wei H M, Kang Y H, Merrill G F
Graduate Program in Physiology, Rutgers University, New Brunswick, New Jersey 08903.
Am J Physiol. 1988 May;254(5 Pt 2):H1004-9. doi: 10.1152/ajpheart.1988.254.5.H1004.
Isolated, perfused guinea pig hearts were infused with intracoronary adenosine deaminase to investigate the contribution of endogenous adenosine to the coronary vasodilation of global myocardial hypoxia. Coronary perfusate pressure was held constant at 70 cmH2O throughout the experiment. We measured retrograde aortic inflow (assumed to equal total antegrade coronary flow) for 3-5 min of hypoxia before and 4 min after initiation of intracoronary adenosine deaminase infusion (4 U.g-1.min-1). In the absence of adenosine deaminase mild global hypoxia increased coronary perfusate flow 60%. In the presence of adenosine deaminase the response was limited to a 5% increment. Myocardial O2 consumption was significantly reduced during hypoxia in the presence of adenosine deaminase. In a second group of hearts, moderate global hypoxia increased coronary perfusate flow 125%. This was limited to a 53% increment in the presence of adenosine deaminase. Adenosine deaminase vehicle had no measurable effect on coronary perfusate flow responses to repeat mild hypoxia in a third group of hearts. We conclude that endogenous adenosine is singularly important in the coronary vasodilation of mild global myocardial hypoxia, but that other regulatory mechanisms might also contribute during moderate hypoxia.
将离体灌注的豚鼠心脏冠状动脉内注入腺苷脱氨酶，以研究内源性腺苷对整体心肌缺氧时冠状动脉血管舒张的作用。在整个实验过程中，冠状动脉灌注压维持在70 cmH₂O不变。我们在冠状动脉内注入腺苷脱氨酶（4 U·g⁻¹·min⁻¹）前3 - 5分钟及注入后4分钟测量缺氧时的逆行主动脉血流量（假定等于总的冠状动脉前向血流量）。在没有腺苷脱氨酶的情况下，轻度整体缺氧使冠状动脉灌注流量增加60%。在有腺苷脱氨酶存在时，该反应仅限于增加5%。在有腺苷脱氨酶存在的缺氧过程中，心肌耗氧量显著降低。在第二组心脏中，中度整体缺氧使冠状动脉灌注流量增加125%。在有腺苷脱氨酶存在时，这仅限于增加53%。在第三组心脏中，腺苷脱氨酶溶剂对重复轻度缺氧时的冠状动脉灌注流量反应没有可测量的影响。我们得出结论，内源性腺苷在轻度整体心肌缺氧时的冠状动脉血管舒张中起非常重要的作用，但在中度缺氧时其他调节机制可能也起作用。
