Receptor binding

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Schematic representation of the subunit organizaton in the most abundant heteromeric receptor complex: a. embryonic muscle nicotinic acetylcholine receptor (nAChR), b. neuronal nAChR, c. glycine receptors, and d. GABAA receptors. The circles indicate the location of the agonist binding site at the interface between the subunits in nAChR and GABAA receptors. The square indicates the location of the benzodiazapine binding site. The depicted GABAA receptor model is the general model with at least one GABA and one benzodiazepine binding site. The number of different binding sites on the GABAA receptor depends on the final stoichiometry of the pentameric complex. Adult muscle nAChR has the stoichiometry (alpha 1)2beta epsilon delta.