RT Journal Article
SR Electronic
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
FD American Society for Pharmacology and Experimental Therapeutics
SP 248
OP 254
DO 10.1124/mol.55.2.248
VO 55
IS 2
A1 Rothlin, Carla V.
A1 Katz, Eleonora
A1 Verbitsky, Miguel
A1 Elgoyhen, A. Belén
YR 1999
UL http://molpharm.aspetjournals.org/content/55/2/248.abstract
AB 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.