Tang J P, Xu Z Q, Douglas F L, Rakhit A, Melethil S
School of Pharmacy, University of Missouri-Kansas City 64108.
Life Sci. 1993;53(25):PL417-20. doi: 10.1016/0024-3205(93)90033-y.
A previous communication from this laboratory reported that brain uptake of libenzapril, a small polar molecule, was enhanced in chronic hypertension (1). The objective of this investigation was to determine if this was a more generalized phenomenon. Therefore, experiments were undertaken to examine the effect of chronic hypertension on the brain uptake of tryptophan (an amino acid with high brain permeability) and glutamic acid (one with low permeability). Brain concentrations of these two amino acids were 5- to 12-fold greater in chronic hypertensive rats, as compared to normotensive rats; the corresponding brain uptake index (BUI) values were 2- to 5-fold higher in the former group. Since blood-brain barrier transport of amino acids involve both saturable (carrier) and non-saturable (most likely, diffusion via pores) mechanisms, data from this study show that hypertension can enhance BBB transport of amino acids by affecting one or both of these pathways.
该实验室之前的一份通讯报道称，在慢性高血压患者中，小极性分子赖诺普利的脑摄取量会增加（1）。本研究的目的是确定这是否是一种更普遍的现象。因此，我们进行了实验，以研究慢性高血压对色氨酸（一种脑通透性高的氨基酸）和谷氨酸（一种脑通透性低的氨基酸）脑摄取的影响。与正常血压大鼠相比，慢性高血压大鼠脑中这两种氨基酸的浓度高5至12倍；前一组相应的脑摄取指数（BUI）值高出2至5倍。由于氨基酸的血脑屏障转运涉及可饱和（载体）和不可饱和（很可能是通过孔隙扩散）两种机制，本研究的数据表明，高血压可通过影响这些途径中的一种或两种来增强血脑屏障对氨基酸的转运。
