Effects of cerebral hypothermia on brain tissue impedance and extracellular ion concentrations

脑低温对脑组织阻抗和细胞外离子浓度的影响

• 批准号: 10671320
• 负责人: MORI Kentaro
• 金额: $ 0.83万
• 依托单位: Juntendo University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1998
• 资助国家: 日本
• 起止时间: 1998 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10671320/
• 关键词: hypothermia; cerebral ischemia; glutamate; vasoconstriction; brain impedance; extracellular ion; water channel; ion channel; hypothermia; cerebral ischemia; glutamate; vasoconstriction; brain impedance; extracellular ion; water channel; ion channel

The purpose of this research project was to investigate the protective mechanismas of cerebral hypothermia and to improve its therapeutic effects.1. Effects of cerebral hypothermia on cerebral blood flow and metabolismWe investigated the effects of hypothermia on cerebral blood flow (CBF) and metabolism (CMROィイD22ィエD2, AVDOィイD22ィエD2), cerebral venous oxygen saturation (ScvOィイD22ィエD2), cerebral blood volume (CBV), and cerebral vascular resistance (CVR) using 34 anesthetized cat. Brain temperature was controlled from 37 to 25℃. AVDOィイD22ィエD2 increased significantly at 29℃, ScvOィイD22ィエD2 decreased significantly at 29℃, CBV decreased significantly at 29℃, and CVR increased significantly at 29℃. The combined effect of hypothermia with vasopressor (noradrenalin) administration improved all these metabolic parameters. These results suggest that hypothermia below 30℃ may cause cerebral vasoconstriction and misery perfusion in the brain. This potential risk of relative ischemia can be avoided b … More y combination with vasopressor administration.2. Effects of cerebral hypothermia on brain tissue impedane and extracellular ion concentrationsWe investigated the effects of mild cerebral hypothermia on brain tissue impedance (brain extracellular space: ECS) and extracellular ion concentrations ([NaィイD1+ィエD1] ィイD2eィエD2, [KィイD1+ィエD1] ィイD2eィエD2) under cerebral ischemia using anesthetized 11 rats. After global ischemia, ECS began to decrease (post-ischemic cell swelling) at 32±5 sec and then [NaィイD1+ィエD1] ィイD2eィエD2 started to decrease (NaィイD1+ィエD1 ion influx into cells) at 83±30 sec. Hypothermia significantly prolonged both changes of ECS and extracellular ion concentrations. These result shows that cerebral ischemic cell swelling start to occur earlier than extracellular NaィイD1+ィエD1 ion influx into cells. This fact makes it difficult to explain the mechanism of the cell swelling by the former theory that swelling is caused by isotonic water movement after NaィイD1+ィエD1 influx. It is suggested that a depletion of intracellular ATP causes dephospholization of water channel (aquaporin 4) and directly open this water channel. Cerebral hypothermia may influence this water channel directly and prolong the opening of this water channel. Less

该研究项目的目的是研究脑体温过低的保护机制并改善其治疗作用。1。脑体温过低对脑血流量和代谢性的影响研究了体温过低对脑血流（CBF）和代谢的影响（CMROII D22 E D2，AVDOIII D22 E D2），脑静脉氧气饱和（SCVOII D2 ED2 ED2 ED2），Cerebral d2 e D2，Cerebral d2 e D2）使用34个麻醉猫的血管抗性（CVR）。大脑温度从37到25℃控制。 Avdoi D22E D2在29℃时显着增加，SCVOI D22E D2在29℃时显着降低，CBV在29℃时显着下降，CVR显着下降，而在29℃时，CVR显着增加。体温过低与加压剂（去甲肾上腺素）的综合作用改善了所有这些代谢参数。这些结果表明，低于30的体温过低可能导致大脑中的脑血管收缩和痛苦灌注。可以避免使用相对缺血的潜在风险与加压剂给药更多的组合。2。脑体温过低对脑组织抗抑制剂和细胞外离子浓度的影响我们研究了轻度脑体温过低对脑组织阻抗（脑外部空间：ECS）和细胞外离子浓度的影响（[NAY D1+E D1] D2E D2E D2 D2，[KII D1 d1 d1+e d1+e d1 d2]麻醉11只老鼠。全球性缺血之后，EC在32±5 sec下开始降低（缺血后细胞肿胀），然后[NAY D1+E D1] D2E D2在83±30 sec下开始降低（NAY D1+E D1离子对细胞的影响）。体温过低显着延长ECS和细胞外离子浓度的变化。这些结果表明，脑缺血细胞吞咽开始早于细胞外NAII D1+IE D1离子对细胞的影响。这一事实使得很难解释前者吞咽细胞的机制，即肿胀是由NAII D1+IE D1影响后的等渗水运动引起的。建议细胞内ATP的耗竭会导致水通道的去磷化（Aquaporin 4）并直接打开该水通道。脑体温过低可能直接影响该水通道并延长该水通道的开口。较少的