Ray John, Noll Frank, Daut Jürgen, Hanley Peter J
Institut für Normale und Pathologische Physiologie, Universität Marburg, 35037 Marburg, Germany.
Am J Physiol Heart Circ Physiol. 2002 Apr;282(4):H1495-501. doi: 10.1152/ajpheart.00696.2001.
The effects of long-chain (LC) fatty acids on rate of heat production (heat rate) and mitochondrial membrane potential (DeltaPsi) of intact guinea pig cardiac muscle were investigated at 37 degrees C. Heat rate of ventricular trabeculae was measured with microcalorimetry, and DeltaPsi was monitored in isolated ventricular myocytes with either JC-1 or tetramethylrhodamine ethyl ester (TMRE). Methyl-beta-cyclodextrin was used as fatty acid carrier. Application of 400 microM oleate or linoleate increased resting heat rate by approximately 30% and approximately 25%, respectively. When LC fatty acid was supplied as sole metabolic substrate, resting heat rate was decreased by 3-mercaptopropionic acid. In TMRE-loaded myocytes, neither 40-80 microM oleate nor 40 microM linoleate affected DeltaPsi. At a higher concentration (400 microM) both oleate and linoleate increased TMRE fluorescence by approximately 20% of maximum, obtained using 2,4-dinitrophenol (100 microM), indicating a depolarization of the inner mitochondrial membrane. We conclude that LC fatty acids, at sufficiently high concentration, increase heat rate and decrease DeltaPsi in intact cardiac muscle, consistent with a protonophoric uncoupling action. These effects may contribute to the high metabolic rate after reperfusion of postischemic myocardium.
在37℃下研究了长链（LC）脂肪酸对完整豚鼠心肌产热速率（热速率）和线粒体膜电位（ΔΨ）的影响。用微量量热法测量心室小梁的热速率，并用JC-1或四甲基罗丹明乙酯（TMRE）监测分离的心室肌细胞中的ΔΨ。甲基-β-环糊精用作脂肪酸载体。施加400μM油酸酯或亚油酸酯分别使静息热速率提高约30%和约25%。当LC脂肪酸作为唯一的代谢底物供应时，3-巯基丙酸可降低静息热速率。在加载TMRE的心肌细胞中，40-80μM油酸酯和40μM亚油酸酯均不影响ΔΨ。在较高浓度（400μM）下，油酸酯和亚油酸酯均使TMRE荧光增加约为使用2,4-二硝基苯酚（100μM）时获得的最大值的20%，表明线粒体内膜去极化。我们得出结论，在足够高的浓度下，LC脂肪酸可增加完整心肌的热速率并降低ΔΨ，这与质子载体解偶联作用一致。这些作用可能有助于缺血后心肌再灌注后的高代谢率。
