试论中药归经入脑

归经是指药物对机体某一部分的选择性作用。传统归经理论主要以临床疗效为归经依据。现代医学认为，神志活动是脑的生理功能。现代药理也证明很多中药对脑具有直接或间接的作用，这也说明这些中药的药效作用部位确实是脑。对脑有直接作用的中药具有维护血脑屏障的结构完整，改善其功能，或扩张脑血管，增加脑血流量，降低血粘度的功能。对脑有间接作用的中药，可以通过清除自由基、阻止神经细胞凋亡的启动等，间接改善脑功能。

A Probe into Relating Chinese Medicine to Brain and Channel Tropism

Channel tropism refers to the theory that relates the therapeutic action of drugs to a certain parts of the body. Traditionally, the theory was based on clinical effects, but modern theory holds that mental activities are the functions of the brain. And modern pharmacology also confirmed that many drugs of TCM make direct or indirect effects on the brain. Those drugs that make direct effects on the brain bear the ability of maintaining the shelter of the brain structurally intact, improving the function of the brain, expanding blood vessel of the brain, raising the volume of blood flow in the brain and thinning blood viscosity. Those drugs that make indirect effects on the brain bear the ability of improving the function of the brain through eliminating free radical and preventing nerve cells from waning.