(''R'')-3-Nitrobiphenyline is a drug which acts as an α-adrenergic
agonist
An agonist is a chemical that activates a Receptor (biochemistry), receptor to produce a biological response. Receptors are Cell (biology), cellular proteins whose activation causes the cell to modify what it is currently doing. In contrast, an R ...
, selective for the α subtype, as well as being a weak
antagonist
An antagonist is a character in a story who is presented as the main enemy or rival of the protagonist and is often depicted as a villain.α and α subtypes. It has been used in scientific research to characterize the binding and functional properties of the α subtype.