Markovitz D C, Fernstrom J D
Science. 1977 Sep 2;197(4307):1014-5. doi: 10.1126/science.887937.
The rise in levels of aldomet in the brains of rats after an injection of the alpha-methylated amino acid was depressed when large neutral amino acids, but not acidic amino acids, were coadministered with the drug. This result suggests that aldomet is transported into brain by the carrier for natural large neutral amino acids. The prior ingestion of a carbohydrate meal, which lowers levels of neural amino acids in the serum, enhanced the uptake of aldomet into brain; the consumption of a protein-containing meal inhibited the subsequent uptake of aldomet into the brain. Antecedent diet can thus affect the availability of aldomet to the central nervous system; the mechanism of this effect probably involves the blood-brain barrier uptake system for large neutral amino acids.
当与α-甲基化氨基酸一起注射时，若同时给予大中性氨基酸而非酸性氨基酸，大鼠脑中醛甲硫氨酸水平的升高会受到抑制。这一结果表明，醛甲硫氨酸是通过天然大中性氨基酸的载体转运进入脑内的。预先摄入碳水化合物餐会降低血清中神经氨基酸的水平，从而增强醛甲硫氨酸向脑内的摄取；而摄入含蛋白质餐则会抑制随后醛甲硫氨酸向脑内的摄取。因此，先前的饮食可以影响醛甲硫氨酸向中枢神经系统的供应；这种影响的机制可能涉及大中性氨基酸的血脑屏障摄取系统。
