On the other hand: The stereoselectivity of drug action at ion channels

Ion channels are pharmacological receptors with specific drug binding sites. These binding sites define specific structure–function relationships for the actions of drug classes. Interpretation of these structure–function relationships may be complex because of state‐dependent drug‐channel interactions. These state‐dependent interactions determine affinity and access of drug to binding sites and may result in both quantitative and qualitative changes in structure–function relationships including stereoselectivity. A channel‐active drug may exhibit antagonist or activator properties according to membrane potential and the stereoselectivity of interaction may also change with channel state. © 1994 Wiley‐Liss, Inc.