TABLE 1

Influence of lysine and its structural analogs and derivatives on the opioid peptide transport system in SK-N-SH cells

Uptake of [3H]deltorphin II (25 nM) was measured in SK-N-SH cells for 30 min in the presence of NaCl with or without lysine or its structural analogs and derivatives. Final concentration of these compounds during uptake was 1 mM. Data are presented as means ± S.E.

Compound
Deltorphin II Uptake
% Control
pmol/mg protein/30 min
None 3.00 ± 0.19 100
l-Lys 0.26 ± 0.01 9
l-Arg 1.46 ± 0.12 49
γ-Aminobutyrate 2.62 ± 0.13 87
l-Ornithine 1.87 ± 0.08 62
l-Carnitine 2.34 ± 0.12 78
l-Citrulline 2.18 ± 0.06 73
d-Lys 2.60 ± 0.31 87
Trimethyl l-Lys 2.39 ± 0.11 80
l-Lysinamide 2.92 ± 0.09 97
l-Lys-methyl ester 0.28 ± 0.01 9
l-Lys-ethyl ester 0.55 ± 0.05 18
α-N-Acetyl-l-Lys 2.82 ± 0.08 94
ϵ-N-Acetyl-l-Lys 2.38 ± 0.13 79
α-N-Acetyl-l-Lys-methylester 2.37 ± 0.20 79
δ-Aminolevulenic acid 2.68 ± 0.18 89
N-Iminoethyl-l-Lys 2.40 ± 0.15 80
1,5-Diaminopentane 3.24 ± 0.16 108
Hexamethylenediamine 2.83 ± 0.13 94
6-Aminohexanoic acid
2.92 ± 0.18
97