ELECTRICAL-RESISTANCE ACROSS THE BLOOD-BRAIN-BARRIER IN ANESTHETIZED RATS - A DEVELOPMENTAL-STUDY
ELECTRICAL-RESISTANCE ACROSS THE BLOOD-BRAIN-BARRIER IN ANESTHETIZED RATS - A DEVELOPMENTAL-STUDY
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DOI：
10.1113/jphysiol.1990.sp018243
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发表时间：
1990-10-01
影响因子：
5.5
通讯作者：
ABBOTT, NJ
中科院分区：
文献类型：
--
作者：
BUTT, AM;JONES, HC;ABBOTT, NJ
1.通过原位测定17天龄至33天龄麻醉大鼠血脑屏障的跨内皮细胞电阻，以及对10日龄以下胎鼠和新生大鼠血脑屏障中镧的通透性进行了研究。2.17-20天胎儿血脑屏障的阻力为310欧米伽·厘米~2，但对镧不渗透，因此具有介于渗漏和致密上皮之间的性质。3.妊娠21天开始，阻力为1128.00×10~(-2)cm~2，提示血脑屏障紧密，离子通透性低。屏障阻力在出生后几乎没有进一步的变化，在出生28至33天的大鼠中，当脑屏障系统以其他方式成熟时，血管的平均阻力为1462.Omega·cm2。4.在紧密的血脑屏障中，动脉血管的阻力显著高于静脉血管，分别为1490和918。在直径小于50微米的血管中，在正常的60分钟实验期内，血管阻力没有显著变化。5.高渗休克引起血管阻力迅速下降(5分钟内最大)，破坏血脑屏障后，动、静脉血管阻力均为100-300欧姆·厘米~2，且这种效应是可逆的。在使用代谢性毒药(NaCN加碘乙酸酯)和低温后，也有类似的低电阻。6.出生时电阻的增加表明血脑屏障的细胞旁离子通透性降低，这是有效的脑间质液离子调节所必需的。
1. Ion permeability of the blood-brain barrier was studied by in situ measurement of transendothelial electrical resistance in anaesthetized rats aged between 17 days gestation and 33 days after birth, and by electron microscopic examination of lanthanum permeability in fetal and neonatal rats aged up to 10 days old. 2. The blood-brain barrier in 17- to 20-day fetuses had a resistance of 310 .OMEGA. cm2 but was impermeable to lanthanum, and therefore had properties intermediate between leaky and tight epithelia. 3. From 21 days gestation, the resistance was 1128 .OMEGA. cm2, indicating a tight blood-brain barrier and low ion permeability. There was little further change in barrier resistance after birth, and in 28- to 33-day rats, when the brain barrier systems are mature in other ways, vessels had a mean resistance of 1462 .OMEGA. cm2. 4. In the tight blood-brain barrier, arterial vessels had a significantly higher resistance than venous vessels, 1490 and 918 .OMEGA. cm2 respectively. In vessels less than 50 .mu.m diameter and within the normal 60 min experimental period, there was no significant variation in vessel resistance. 5. Hyperosmotic shock caused a rapid decay in resistance (maximal within 5 min), and after disruption of the blood-brain barrier, vessel resistance was 100-300 .OMEGA. cm2 in both arterial and venous vessels, and the effect was reversible. After the application of metabolic poisons (NaCN plus iodoacetate) and low temperature there was similarly low electrical resistance. 6. It is concluded that the increase in electrical resistance at birth indicates a decrease in paracellular ion permeability at the blood-brain barrier and is required for effective brain interstitial fluid ion regulation.