Sarmento A, Borges N, Azevedo I
Department of Pharmacology and Therapeutics, Faculty of Medicine, Porto, Portugal.
Naunyn Schmiedebergs Arch Pharmacol. 1991 Jun;343(6):633-7. doi: 10.1007/BF00184295.
The central adrenergic innervation of the cerebral microvessels may play a role in the control of blood-brain barrier permeability. To pursue the study of this hypothesis we investigated the effect of noradrenaline on both the permeability of the blood-brain barrier to sodium fluorescein and on the pinocytotic activity of cerebral endothelial cells in the rat. Noradrenaline, stereotactically injected in the right lateral cerebral ventricle, significantly increased the cerebral extraction ratio of sodium fluorescein in a dose-dependent way. The same effect was induced by phenylephrine. Prostaglandin F2 alpha had no significant effect on the passage of sodium fluorescein through the blood-brain barrier. The effect of noradrenaline (150 micrograms) on the cerebral extraction ratio of sodium fluorescein was totally blocked by phenoxybenzamine (25 mg/kg i.p., 24 h before noradrenaline). Noradrenaline (150 micrograms) significantly increased the pinocytotic activity of cerebral endothelial cells. Phenoxybenzamine (as above) reduced the effect of noradrenaline on pinocytosis. It is concluded that noradrenaline increases the blood-brain barrier's permeability to sodium fluorescein, most probably through an effect on alpha adrenoceptors. The increase induced in the blood-brain barrier's permeability by noradrenaline seems to be due, at least in part, to an increase in the pinocytotic activity of endothelial cells.
大脑微血管的中枢肾上腺素能神经支配可能在血脑屏障通透性的控制中发挥作用。为了对这一假说进行研究，我们调查了去甲肾上腺素对大鼠血脑屏障对荧光素钠的通透性以及对脑内皮细胞胞饮活性的影响。通过立体定位将去甲肾上腺素注射到右侧侧脑室后，荧光素钠的脑摄取率以剂量依赖的方式显著增加。苯肾上腺素也诱导了相同的效果。前列腺素F2α对荧光素钠通过血脑屏障的过程没有显著影响。去甲肾上腺素（150微克）对荧光素钠脑摄取率的影响被酚苄明（25毫克/千克腹腔注射，在去甲肾上腺素注射前24小时）完全阻断。去甲肾上腺素（150微克）显著增加了脑内皮细胞的胞饮活性。酚苄明（如上所述）降低了去甲肾上腺素对胞饮作用的影响。得出的结论是，去甲肾上腺素增加了血脑屏障对荧光素钠的通透性，很可能是通过对α肾上腺素能受体的作用。去甲肾上腺素诱导的血脑屏障通透性增加似乎至少部分是由于内皮细胞胞饮活性的增加。
