Figure 1. Scatchard plots of transport-specific 5-[³H]HT binding to intact L-S1 cells.

The concentration of 5-[³H]HT ranged from 0.1 to 0.5 μm. Specific binding levels (‘B’) were measured as displacement of total binding by either 100 nm (near the IC₅₀ value) or 100 μm imipramine (fully inhibitory concentration). Each point is the mean of six measurements.