Energy metabolism, ion homeostasis, and evoked potentials in anoxic turtle brain.
Energy metabolism, ion homeostasis, and evoked potentials in anoxic turtle brain.
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缺氧龟脑中的能量代谢、离子稳态和诱发电位。
DOI：
10.1152/ajpregu.1989.257.4.r854
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发表时间：
1989
期刊：
影响因子：
--
通讯作者：
Sick,TJ
中科院分区：
文献类型：
--
作者：
Chih,CP;Feng,ZC;Rosenthal,M;Lutz,PL;Sick,TJ
与哺乳动物的大脑不同，龟脑在长时间缺氧期间保持离子稳态并避免缺氧去极化。通过将细胞ATP水平的变化与细胞外K+（K+o）和诱发电位活动相关联，研究了海龟脑避免和恢复缺氧去极化的机制。ATP水平维持在6小时的缺氧，尽管显着减少能源生产，但ATP的氧化磷酸化和糖酵解抑制过程中降低。K+O活性在缺氧6小时内无变化，但随着ATP水平的降低而升高。海龟大脑中的离子稳态似乎与ATP水平有关，但不受能量产生速率的影响。相反，当ATP水平保持不变时，诱发电位的幅度下降，但能量产生率下降。缺氧去极化后ATP和K+o水平恢复，但诱发电位活动没有恢复。这些数据表明，龟脑缺氧生存的基本策略是通过维持ATP水平来避免缺氧去极化。
Unlike the mammalian brain, the turtle brain maintains ion homeostasis and avoids anoxic depolarization during prolonged anoxia. The mechanisms by which turtle brains avoid and recover from anoxic depolarization were investigated by relating changes in cellular ATP levels to extracellular K+ (K+o) and evoked potential activities after 6 h of anoxia and during anoxic depolarization induced by superfusion of the brain surface with iodoacetate during anoxia. ATP levels were maintained during 6 h of anoxia despite marked decreases in energy production, but ATP was lowered during inhibition of both oxidative phosphorylation and glycolysis. K+o activity was unchanged during 6 h of anoxia but increased when ATP levels decreased. Ion homeostasis in the turtle brain appears to be linked to ATP levels but is unaffected by rate of energy production. In contrast, amplitudes of evoked potentials decreased when ATP levels were maintained, but rate of energy production declined. ATP and K+o levels recovered after anoxic depolarization, but evoked potential activity was not restored. These data suggest that the basic strategy for turtle brain to survive anoxia is to avoid anoxic depolarization by maintaining ATP levels.