TY - JOUR T1 - The α9 Nicotinic Acetylcholine Receptor Shares Pharmacological Properties with Type A γ-Aminobutyric Acid, Glycine, and Type 3 Serotonin Receptors JF - Molecular Pharmacology JO - Mol Pharmacol SP - 248 LP - 254 DO - 10.1124/mol.55.2.248 VL - 55 IS - 2 AU - Carla V. Rothlin AU - Eleonora Katz AU - Miguel Verbitsky AU - A. Belén Elgoyhen Y1 - 1999/02/01 UR - http://molpharm.aspetjournals.org/content/55/2/248.abstract N2 - In the present study, we provide evidence that the α9 nicotinic acetylcholine receptor (nAChR) shares pharmacological properties with members of the Cys-loop family of receptors. Thus, the type A γ-aminobutyric acid receptor antagonist bicuculline, the glycinergic antagonist strychnine, and the type 3 serotonin receptor antagonist ICS-205,930 block ACh-evoked currents in α9-injected Xenopus laevis oocytes with the following rank order of potency: strychnine > ICS-205,930 > bicuculline. Block by antagonists was reflected in an increase in the acetylcholine (ACh) EC50 value, with no changes in agonist maximal response or Hill coefficient, which suggests a competitive type of block. Moreover, whereas neither γ-aminobutyric acid nor glycine modified ACh-evoked currents, serotonin blocked responses to ACh in a concentration-dependent manner. The present results suggest that the α9 nAChR must conserve in its primary structure some residues responsible for ligand binding common to other Cys-loop receptors. In addition, it adds further evidence that the α9 nAChR and the cholinergic receptor present at the base of cochlear outer hair cells have similar pharmacological properties. ER -