Energy metabolism of the visual system.
Energy metabolism of the visual system.
复制标题
视觉系统的能量代谢。
DOI：
10.2147/eb.s9078
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发表时间：
2010
期刊：
影响因子：
4.4
通讯作者：
Wong-Riley MT
中科院分区：
文献类型：
--
作者：
Wong-Riley MT
视觉系统是大脑中对能量要求最高的系统之一。能量的货币是 ATP，它是通过线粒体的氧化代谢最有效地产生的。 ATP 支持多种神经元功能。最重要的是去极化后膜电位的复极化。神经元活动、ATP 生成、血流量、耗氧量、葡萄糖利用和线粒体氧化代谢都是相互关联的。在视网膜中，光转导、神经递质利用和蛋白质/细胞器运输都依赖于能量，但去极化后的复极化消耗了大部分能量。光感受器内节的复极化维持暗电流。去极化兴奋性谷氨酸神经传递后，视觉通路上所有神经元的复极化可保持细胞完整性并允许重新激活。巨细胞通路与细细胞通路、某些物种中的ON通路与OFF通路（以及其他物种中的相反）以及视觉皮层中的专门功能表征中较高的代谢活性都反映了对特定视觉属性的处理的更加重视。神经元活动和能量代谢是细胞甚至分子水平上紧密耦合的过程。能量代谢缺陷，例如糖尿病、线粒体 DNA 突变、线粒体蛋白功能障碍和氧化应激，可能导致视网膜病变、视力缺陷、神经元变性，甚至最终失明。
The visual system is one of the most energetically demanding systems in the brain. The currency of energy is ATP, which is generated most efficiently from oxidative metabolism in the mitochondria. ATP supports multiple neuronal functions. Foremost is repolarization of the membrane potential after depolarization. Neuronal activity, ATP generation, blood flow, oxygen consumption, glucose utilization, and mitochondrial oxidative metabolism are all interrelated. In the retina, phototransduction, neurotransmitter utilization, and protein/organelle transport are energy-dependent, yet repolarization-after-depolarization consumes the bulk of the energy. Repolarization in photoreceptor inner segments maintains the dark current. Repolarization by all neurons along the visual pathway following depolarizing excitatory glutamatergic neurotransmission preserves cellular integrity and permits reactivation. The higher metabolic activity in the magno- versus the parvo-cellular pathway, the ON- versus the OFF-pathway in some (and the reverse in other) species, and in specialized functional representations in the visual cortex all reflect a greater emphasis on the processing of specific visual attributes. Neuronal activity and energy metabolism are tightly coupled processes at the cellular and even at the molecular levels. Deficiencies in energy metabolism, such as in diabetes, mitochondrial DNA mutation, mitochondrial protein malfunction, and oxidative stress can lead to retinopathy, visual deficits, neuronal degeneration, and eventual blindness.