Spreading depolarization triggered by elevated potassium is weak or absent in the rodent lower brain
Spreading depolarization triggered by elevated potassium is weak or absent in the rodent lower brain
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DOI：
10.1177/0271678x16657344
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发表时间：
2017-05-01
影响因子：
6.3
通讯作者：
Brisson, C. Devin
中科院分区：
文献类型：
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作者：
Andrew, R. David;Hsieh, Yi-Ting;Brisson, C. Devin
我们在大鼠和小鼠的活体冠状切片上检测了哪些大脑区域产生钾触发的扩散性去极化(SDKt)。这项技术模拟了皮层扩散抑制，这是完整大脑中偏头痛先兆的基础。通过增加BaT[K+](O)诱发SDKt事件，并记录为透光率升高的传播前沿，代表新皮质、海马区、纹状体和丘脑灰质的一过性神经元肿胀。相反，除了靠近脑干背侧表面的核团外，SDKt在下丘脑和脑干的核团中未见表达。在大鼠脑片上，单个神经元在SDKt过程中出现全细胞电流钳制。“高级”神经元去极化到接近零毫伏，表明SDKt的产生。相比之下，下丘脑和脑干中的七种神经元只缓慢去极化，不产生SDKt，这支持了我们的成像发现。因此，SDKt不是CNS神经元的缺省，而是表现出类似于缺氧去极化的区域特异性敏感性，我们提出的这种敏感性与某个区域对创伤性脑损伤的易感性有关。在高级大脑中，SDKt可能是一种残留的扩散性去极化，最初进化为关闭和血管收缩更容易受到冲击和挫伤的灰质区域。
We examined in live coronal slices from rat and mouse which brain regions generate potassium-triggered spreading depolarization (SDKt). This technique simulates cortical spreading depression, which underlies migraine aura in the intact brain. An SDKt episode was evoked by increasing bath [K+](o) and recorded as a propagating front of elevated light transmittance representing transient neuronal swelling in gray matter of neocortex, hippocampus, striatum, and thalamus. In contrast, SDKt was not imaged in hypothalamic nuclei or brainstem with exception of those nuclei near the dorsal brainstem surface. In rat slices, single neurons were whole-cell current clamped during SDKt. "Higher" neurons depolarized to near zero millivolts indicating SDKt generation. In contrast, seven types of neurons in hypothalamus and brainstem only slowly depolarized without generating SDKt, supporting our imaging findings. Therefore, SDKt is not a default of CNS neurons but rather displays a region-specific susceptibility, similar to anoxic depolarization, which we have proposed is correlated with a region's vulnerability to traumatic brain injury. In the higher brain, SDKt may be a vestigial spreading depolarization that originally evolved to shut down and vasoconstrict gray matter regions more exposed to impact and contusion.