Molecular actions of propofol on human 5-HT3A receptors: enhancement as well as inhibition by closely related phenol derivatives.

Background: 5-Hydroxytryptamine type 3 (5-HT3) receptors are excitatory ligand-gated ion channels which are involved in postoperative nausea and vomiting. They are depressed by the anesthetic propofol, which, in contrast, enhances the activity of inhibitory ligand-gated ion channels such as gamma-aminobutyric acid type A receptors and glycine receptors. To investigate the molecular mechanisms responsible for these contrasting actions, we examined the kinetics of the action of propofol and its lesser hydrophobic derivatives 2-isopropylphenol and phenol on human 5-HT3A receptors.