Penetration of Glutamate into Brain of 7-day-old Rats
Penetration of Glutamate into Brain of 7-day-old Rats
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谷氨酸对 7 日龄大鼠大脑的渗透
DOI：
10.1023/b:mebr.0000007102.78696.e3
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发表时间：
1997
影响因子：
3.6
通讯作者：
R. Hawkins
中科院分区：
文献类型：
--
作者：
J. Viña;M. DeJoseph;P. A. Hawkins;R. Hawkins
在7日龄大鼠（平均血浆谷氨酸114 μM）和皮下注射谷氨酸的大鼠（平均血浆谷氨酸2，670 μM）的脑中，通过定量放射自显影术测量血脑屏障对谷氨酸的渗透性。通过向下腔静脉注射[14 C]谷氨酸盐开始测量谷氨酸盐渗透性，并在1分钟时处死7日龄大鼠，以避免[14 C]谷氨酸盐代谢产物在血浆中蓄积。谷氨酸以缓慢的速度进入大脑，平均渗透率-表面积乘积为12 μl·min-1·g-1，除了那些已知有窗孔毛细血管的区域。因此，谷氨酸很容易进入并积聚在放射性定位的室周器官中。尽管7日龄大鼠的大脑皮层、下丘脑和中脑这三个具有血脑屏障的区域的渗透性与成年大鼠相似，但具有血脑屏障的其他脑区域的渗透性约为成年大鼠的1.5-1.9倍。7日龄大鼠脑的更大的渗透性可能反映了血脑屏障的不成熟程度。
The permeability of the blood-brain barrier to glutamate was measured by quantitative autoradiography in brains of 7-day-old rats (average plasma glutamate 114 μM) and rats injected subcutaneously with glutamate (average plasma glutamate 2,670 μM). Measurements of glutamate permeability were initiated by the injection of [14C]glutamate into the inferior vena cava and the 7-day-old rats sacrificed at 1 minute to avoid the accumulation of [14C]glutamate metabolites in plasma. Glutamate entered the brain at a slow rate, with an average permeability-surface area product of 12 μl·min−1·g−1, except in those areas known to have fenestrated capillaries. Thus, glutamate readily entered and accumulated in circumventricular organs where the radioactivity was localized. Although three areas with a blood-brain barrier, the cerebral cortex, the hypothalamus and the midbrain, of 7-day-old rats had permeabilities similar to adult rats, the other areas of the brain with a blood-brain barrier had a permeability about 1.5-1.9 times that of adult rats. The greater permeability of the brain of 7-day-old rats may reflect the degree of immaturity of the blood-brain barrier.