Merhige M E, Ekas R, Mossberg K, Taegtmeyer H, Gould K L
Department of Medicine, University of Texas Medical School, Houston 77225.
Circ Res. 1987 Nov;61(5 Pt 2):II124-9.
Uptake of radiolabelled deoxyglucose out of proportion to reduced coronary flow demonstrated by positron emission tomography has been used to identify reversibly ischemic, viable myocardium. For this concept to be applied reliably in the clinical setting, factors that may depress glucose availability independent of tissue viability, such as adrenergic stimulation and substrate competition, must be examined. Accordingly, we studied the effect of catecholamine stimulation by dopamine on myocardial glucose uptake in vivo using chronically instrumented, intact dogs and positron emission tomography. We measured myocardial activity of [2-18F]-2-deoxyglucose (FDG) and 82Rb in glucose-loaded animals randomly studied during dopamine infusion, during insulin infusion, and then during their combined infusion. Myocardial FDG uptake was significantly decreased when animals were treated with dopamine, compared with treatment in the same animals with insulin. When insulin was added to the dopamine infusion, myocardial FDG uptake was restored. In contrast, myocardial activity of 82Rb, which is taken up in proportion to coronary flow, was similar under all three experimental conditions. Plasma glucose, free fatty acid, and lactate concentrations were determined before and during each infusion. The depression of myocardial FDG activity seen during dopamine infusion and its reversal with addition of insulin can be explained on the basis of effects of these hormones on substrate availability and competition.
正电子发射断层扫描显示，放射性标记的脱氧葡萄糖摄取与冠状动脉血流减少不成比例，已被用于识别可逆性缺血的存活心肌。为了在临床环境中可靠地应用这一概念，必须研究那些可能降低葡萄糖可用性而与组织活力无关的因素，如肾上腺素能刺激和底物竞争。因此，我们使用长期植入仪器的完整犬类和正电子发射断层扫描，研究了多巴胺对体内心肌葡萄糖摄取的儿茶酚胺刺激作用。我们在葡萄糖负荷的动物中，在多巴胺输注期间、胰岛素输注期间以及联合输注期间随机测量了[2-18F]-2-脱氧葡萄糖（FDG）和82Rb的心肌活性。与用胰岛素治疗同一动物相比，用多巴胺治疗动物时心肌FDG摄取显著降低。当胰岛素添加到多巴胺输注中时，心肌FDG摄取恢复。相比之下，与冠状动脉血流成比例摄取的82Rb的心肌活性在所有三种实验条件下相似。在每次输注之前和期间测定血浆葡萄糖、游离脂肪酸和乳酸浓度。多巴胺输注期间心肌FDG活性的降低及其添加胰岛素后的逆转可以基于这些激素对底物可用性和竞争的影响来解释。
