Enhancement of benzodiazepine receptor binding by L-lysine is chloride-dependent and due to increase in binding affinity.

L-Lysine enhanced specific [3H]flunitrazepam binding dose dependently on extensively washed bovine brain membrane in vitro. This enhancement was stimulated by chloride ions dose dependently. Scatchard analysis indicated this enhancement by L-lysine to be due to increase in binding affinity (KD) with no change in receptor density (Bmax). Since enhancement of [3H]flunitrazepam binding by L-lysine was partially inhibited by picrotoxinin, L-lysine may act on a distinct picrotoxinin-sensitive site which was distinct from the gamma-aminobutyric acid receptor site. This binding site, however, appears to have some features resembling that of the central nervous system-depressant barbiturates.