Hyperbaric oxygen depolarizes solitary complex neurons in tissue slices of rat medulla oblongata.
Hyperbaric oxygen depolarizes solitary complex neurons in tissue slices of rat medulla oblongata.
复制标题
高压氧使大鼠延髓组织切片中的孤立复杂神经元去极化。
DOI：
10.1007/0-306-46825-5_45
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发表时间：
2000
影响因子：
--
通讯作者：
Dean,JB
中科院分区：
文献类型：
--
作者：
Mulkey,DK;Henderson3rd,RA;Dean,JB
3个大气压绝对压力（ATA）下的高压氧（HBO 2）对哺乳动物的中枢神经系统是有毒的，这是由于过量的自由基产生。目前还没有研究表明≤ 3ATA的O2对哺乳动物脑干神经元膜电位和放电频率的影响。同样，也没有研究确定≤3 ATA压力/次对脑干神经元的影响。因此，我们在1.ATA下对切片（300 μ大鼠延髓尾部，保持在72升高压舱内）中的孤立复合神经元进行细胞内记录。氦是惰性的，在中等程度的高气压下没有麻醉作用，用于流体静力学压缩浸没的脑切片以确定压力本身的影响。组织氧张力和细胞外pH值也进行了测量，在暴露于高压气体。19个神经元中有6个细胞受到高浓度氦的影响，5个细胞去极化，1个细胞超极化。输入电阻（Rm）增加（n=1）或降低（n = 2）。当对照灌注液（0.95ATO_2）转换为98%O_2饱和灌注液（平衡CP_2，PH=7.3·7.4，pO_（223 -34）ATA;暴露2-18分钟）时，13个神经元中有8个去极化，5个不敏感。在8个O反应神经元中，Rmeither增加（n 5）。下降（n = 2）或不变（n= 3）。HBOP 2去极化的8个神经元中有3个也被高压氦去极化，通常伴随着Rm的额外变化。我们得出结论，流体静压（氦）和HBO 2独立地增加某些孤立复合神经元的兴奋性。我们推测，这些反应有助于，在一定程度上，神经事件之前或发生在中枢神经系统O2中毒。
Hyperbaric oxygen (HBO2)at 3 atmospheres absolute (ATA) pressure is toxic to the mammalian CNS due to excessive free radical production. No study has ever determined the effects of ≤3 ATA of O2on the membrane potential and firing rate of neurons in the mammalian brainstem. Likewise, no study has ever determined the effects of ≤3 ATA pressureper seon brainstem neurons. Accordingly, we initiated intracellular recordings at 1 .ATA in solitary complex neurons in slices (300 μ of rat caudal medulla oblongata that were maintained inside a 72 liter hyperbaric chamber. Helium, which is inert and without narcotic effect at moderate levels of hyperbaria, was used to hydro-statically compress the submerged brain slice to determine the effects of pressureper se. Tissue oxygen tension and extracellular pH were also measured during exposure to hyperbaric gases. Six of 19 neurons were affected by hyperburic helium; 5 cells were depolarized and 1 cell was hyperpolanzcd. Input resistance (Rm)either increased (n=1)or decreased (n 2) When control perfusatc (0.95 ATA O2) was switched to perfusate saturated with 98%O2(balance CP2, PH=7.3•7.4, pO223–34 ATA; 2–18 minutes of exposure) in a separate pressure vessel, 8 of 13 neurons were depolarized and 5 neurons were insensitive. In the 8 O-responsive neurons, Rmeither increased (n 5). decreased (n 2) or was unchanged (n=⌋). Three of 8 neurons depolarized by HBOP2were also depolarized by hyperbaric helium, usually with an additional change in RmWe conclude that hydrostatic (helium) pressure and HBO2independently increase excitability in certain solitary complex neurons. We hypothesize that these responses contribute, in part, to neural events that either precede or occur during CNS O2toxicity.