Figure 6.
The S296A mutation does not alter AEA-induced inhibition of 5-HT3A receptors. A, Amino acid alignment of the TM3 region flanking S296 (α1 GlyR) or equivalent residues in other ligand-gated ion channels. B, Representative current records for I5-HT activated by a maximally efficacious concentration (30 μm) of 5-HT before, during and after a continuous incubation with 0.1 μm AEA in HEK-293 cells expressing human 5-HT3ARs. C, Time course of the average AEA inhibition of I5-HT in HEK-293 cells expressing wild-type and S296A mutant 5-HT3A receptors. Each point represents mean ± SE of 5–7 cells. D–F, Comparison of the S296 orientation between α1 GlyR (gray ribbons) and 5-HT3AR (cyan ribbons) transmembrane domains. Side and top views of the transmembrane domains of GlyR (D), 5-HT3AR (E), and their superimposition (F). The sidechain oxygen atoms of S296 (shown as spheres) are colored in red for GlyR and in purple for 5-HT3AR.