Heterogeneities in myocardial flow and metabolism: exacerbation with abnormal excitation.
Heterogeneities in myocardial flow and metabolism: exacerbation with abnormal excitation.
复制标题
心肌血流和代谢的异质性：异常兴奋加剧。
DOI：
10.1016/s0002-9149(99)00250-7
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Li,Z
中科院分区：
文献类型：
--
作者：
Bassingthwaighte,JB;Li,Z
由于局部心肌血流具有明显的异质性--正常心脏的血流范围是正常心脏的6-10倍--而且血流的空间分布在长期和各种条件下是稳定的，因此我们探索了血流和其他生理功能之间的关系。局部脂肪酸摄取和氧气消耗几乎与流量呈线性关系。冠状动脉网络结构和流体动力阻力提供了适当的流动不均一性，但被认为是对局部需求的反应，而不是原因。原因可能是需要局部合成三磷酸腺苷(ATP)，因此流量、底物输送和氧气利用主要由局部ATP水解率驱动，主要由收缩蛋白驱动。这一假设绝不是完全经过检验的。来自不同部位的狗心脏起搏数据、左束支传导阻滞患者的数据以及卸载移植大鼠心脏的数据都指向同一个方向：卸载心室肌导致血流减少和葡萄糖摄取夸大减少。其机制很可能是Taegtmeyer和他的同事发现的，即胎儿基因在肌肉卸载和特定代谢酶和转运蛋白下调的区域的表达。
Because regional myocardial blood flows are remarkably heterogeneous—with a 6- to 10-fold range of flows in normal hearts—and because the spatial profiles of the flows are stable over long periods and over a range of conditions, the relation between flows and other physiologic functions has been explored. Local fatty acid uptake and oxygen consumption are almost linearly related to the flows. Coronary network structure and hydrodynamic resistances give suitable flow heterogeneity but are thought to be a response to local needs rather than being causative. Presumably the cause is the need for adenosine triphosphate (ATP) synthesis locally, and therefore flows, substrate delivery, and oxygen utilization are driven primarily by local rates of ATP hydrolysis, mainly by contractile proteins. This hypothesis is by no means fully tested. Data on pacing dog hearts from different sites, on patients with left bundle branch block, and on unloading transplanted rat hearts, all point in the same direction: unloading ventricular muscle leads to diminished flow and exaggeratedly diminished glucose uptake. The mechanism is likely to be that discovered by Taegtmeyer and colleagues, namely, the expression of fetal genes in regions where the muscle is unloaded and particular metabolic enzymes and transporters are downregulated.