Table 3.

Effect of various compounds on [³H]l-tryptophan uptake by TR-BBB cell lines.

Compounds	Concentration	Relative Uptake
	mM	(% of Control)
Control		100 ± 4
+ Tryptophan	2	7.27 ± 0.9 ***
+ Phenylalanine	2	8.68 ± 0.3 ***
+ Tyrosine	2	14.1 ± 1.0 ***
+ Methionine	2	10.3 ± 7.4 ***
+ Glutamine	2	19.4 ± 1.2 ***
+ Citrulline	2	27.3 ± 1.4 ***
+ Valine	2	38.4 ± 1.8 ***
+ Cysteine	2	41.3 ± 1.3 ***
+ Lysine	2	53.1 ± 4.1 ***
+ Serine	2	58.6 ± 1.5 ***
+ Aspartic acid	2	90.2 ± 3.4
+ Glutamic acid	2	97.4 ± 3.8
+ Taurine	2	102 ± 5
+ Choline	2	110 ± 4

[³H]l-Tryptophan uptake by TR-BBB cell lines at 37 °C for 5 min in the presence or absence of l-type amino acids, taurine and choline at a concentration of 2 mM. Each value represents the mean ± SEM (n = 3–4). *** p < 0.001 denotes significantly different from control.