nh+4 ions , at a concentration ( 0.25 mm ) similar to that found in the plasma of patients with hepatic encephalopathy , cause , in vitro , a significant stimulation of the uptake by brain microvessels of large neutral amino acids , without any effect on the uptake of alpha-methylaminoisobutyric acid , glutamic acid , or lysine .
C0086045
concentration
C0006104
brain