Consistent substrate utilization despite reduced flow in hearts with maintained work.
Consistent substrate utilization despite reduced flow in hearts with maintained work.
复制标题
尽管心脏流量减少，但仍保持工作状态，底物利用率保持一致。
DOI：
10.1152/ajpheart.1983.244.6.h799
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
Bergmann,SR
中科院分区：
文献类型：
--
作者：
Fox,KA;Nomura,H;Sobel,BE;Bergmann,SR
由于流量的改变，基于放射性标记底物积累的外部检测的心肌代谢评估可能会受到改变的底物递送以及改变的工作（伴随代谢需求的变化）的影响。为了确定在确定的减少灌注条件下减少输送是否会限制底物利用，采用了离体兔心脏制剂，其中流量减少，但通过调整左心室舒张末压和心率来保持心肌耗氧量（MVo2）和做功恒定。流量从 1.5 毫升减少到 0.5 毫升。 g-1 。 min-1，而心脏功能在低或高水平的 MVo2 下保持恒定。棕榈酸酯的消耗量保持恒定（48.8+/-11.6和68.8+/-23.3nmol.g-1.min-1），因为提取的棕榈酸酯的比例增加（8.8+/-4至29.1+/-7.2%和10.3+/-3.4至21.0+/-6.1%）。结果表明，尽管流量减少，但在恒定工作负荷下的心脏可以提取越来越多比例的递送底物，使得净利用率保持恒定，直到流量减少到维持细胞功能所需的水平以下。他们认为，在低流量条件下，底物提取受损反映了主要或继发性的心肌代谢抑制，而不是简单地减少了底物的输送。
Assessments of myocardial metabolism based on external detection of accumulation of radiolabeled substrates may be influenced, as a result of alterations in flow, by altered substrate delivery as well as altered work (with concomitant changes in metabolic requirements). To determine whether reduced delivery limits substrate utilization under defined conditions of reduced perfusion, an isolated rabbit heart preparation was employed in which flow was reduced but myocardial oxygen consumption (MVo2) and work were kept constant by adjustment of left ventricular end-diastolic pressure and heart rate. Flow was reduced from 1.5 to 0.5 ml . g-1 . min-1, while work was maintained constant in hearts functioning at either low or high levels of MVo2. Consumption of palmitate remained constant (48.8 +/- 11.6 and 68.8 +/- 23.3 nmol . g-1 . min-1), because the proportion of palmitate extracted increased (8.8 +/- 4 to 29.1 +/- 7.2% and 10.3 +/- 3.4 to 21.0 +/- 6.1%). The results indicate that, despite reduction of flow, hearts at constant work loads can extract increasing proportions of delivered substrates such that net utilization remains constant until flow is reduced below the level required to maintain cellular function. They suggest that, under conditions of low flow, impaired extraction of substrates reflects either primarily or secondarily depressed myocardial metabolism rather than simply decreased delivery of substrate.