In vivo myocardial bioenergetics during acute volume and/or pressure loading in a canine model: a 31P NMR study.
In vivo myocardial bioenergetics during acute volume and/or pressure loading in a canine model: a 31P NMR study.
复制标题
犬模型急性容量和/或压力负荷期间的体内心肌生物能学：31P NMR 研究。
作者：
Osbakken,M;Ligeti,L;Huddell,J;Duska,C;Ponomarenko,I;Chance,B
在13只犬上研究了急性容量和/或压力负荷对心肌代谢和机械功能的影响。通过使用聚乙烯管（5 mm内径）将腹主动脉分流至腔静脉来施加容积负荷。塑料调节器允许打开或关闭分流器。对犬进行肝素化（100单位/kg），以防止分流管凝血。为了研究压力负荷的影响，输注去甲肾上腺素（1 µg/kg/min）。采用心率×收缩压（HR × SBP）、心输出量（CO）、压力×容积功（收缩压×每搏输出量）（P × V）和耗氧量（MVO 2）评价心脏机械功能。用~（31）PNMR测定代谢功能。磷酸肌酸/三磷酸腺苷（PCr/ATP）的比率被用来估计在增加工作负荷期间氧化磷酸化的生物能量调节。HR × SBP、CO、P × V、MVO 2与PCr/ATP相关。尽管存在一些变异性，但通常容量负荷与HR × SBP、CO、P × V和MVO 2增加相关，而在整个负荷期间PCr/ATP无变化，或略有增加或略有减少。这些数据表明，心脏的生物能量学是相当稳定的体积和/或压力负荷和that 31 P光谱方法可以记录这种稳定性和严密的代谢调节在体内负荷条件下。
The effects of acute volume and/or pressure loading on myocardial metabolic and mechanical function were studied in 13 dogs. Volume loads were applied by shunting the abdominal aorta to the vena cava using polyethylene tubing (5 mm inner diameter). A plastic regulator allowed shunts to be opened or closed. Dogs were heparinized (100 units/kg) to prevent shunts from clotting. To study the effects of pressure loading, a norepinephrine infusion (1 µg/kg/min) was administered. Mechanical function of the heart was evaluated using heart rate × systolic blood pressure (HR × SBP), cardiac output (CO), pressure × volume work (systolic blood pressure × stroke volume); (P × V), and oxygen consumption (MVO2) to estimate external myocardial work. Metabolic function was evaluated by31P NMR. Phosphocreatine/adenosine triphosphate (PCr/ATP) ratios were used to estimate the bioenergetic regulation of oxidative phosphorylation during increased work load. HR × SBP, CO, P × V, and MVO2were correlated with PCr/ATP. Although there was some variability, generally volume loading was associated with an increase in HR × SBP, CO, P × V, and MVO2accompanied by no change, or small increases or small decreases in PCr/ATP throughout the loading period. These data indicate that the heart bioenergetics are quite stable during volume and/or pressure loading and that31P spectroscopy methods can document this stability and tight metabolic regulation during in vivo loading conditions.