Varela A, Carregal M, Bruno-Magnasco C, Espósito S, Savino E A
Cátedra de Fisiología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina.
Rev Esp Fisiol. 1992 Sep;48(3):177-83.
Isolated rat atria in hypoxia released lactate into the bathing medium and underwent a decline of the contraction frequency which, in some cases led to a complete cessation of the pacemaker activity. A pronounced fall in the peak developed tension and a rise in the resting tension also appeared. The atria from 24 h fasted rats, which oxidize faster their reserve lipids than those from fed rats, exhibited greater functional disturbances during hypoxia, a lower lactate output and a smaller recovery of peak tension upon reoxygenation. Methyl palmoxirate, which is a selective inhibitor of carnitine palmitoyltransferase I, attenuated the decline of the beating rate and the rise of the resting tension in both groups of rats and the incidence of atrial arrest in the fasted rat group. The fall in the peak tension, lactate output and recovery upon reoxygenation were not altered by the inhibitor. These data indicate that methyl palmoxirate alleviates some of the hypoxic functional derangements. Hence, it may be inferred that inhibiting the oxidation of the fatty acid derived from the endogenous triacylglycerol is beneficial during oxygen-limited conditions and that these effects could not be ascribed to changes in the glycolytic flux.
缺氧状态下的离体大鼠心房会向浴液中释放乳酸，且收缩频率下降，在某些情况下会导致起搏活动完全停止。同时还会出现峰值张力显著下降以及静息张力升高的情况。禁食24小时的大鼠心房比喂食大鼠的心房更快地氧化其储备脂质，在缺氧期间表现出更大的功能紊乱、更低的乳酸输出以及复氧时峰值张力的恢复更小。棕榈酰肉碱甲酯是肉碱棕榈酰转移酶I的选择性抑制剂，它减弱了两组大鼠的心率下降和静息张力升高，以及禁食大鼠组心房停搏的发生率。抑制剂并未改变峰值张力下降、乳酸输出以及复氧时的恢复情况。这些数据表明棕榈酰肉碱甲酯减轻了一些缺氧引起的功能紊乱。因此，可以推断在氧供应受限的情况下，抑制内源性三酰甘油衍生脂肪酸的氧化是有益的，并且这些作用不能归因于糖酵解通量的变化。
