The alpha-1B adrenergic receptor (α1B adrenoreceptor), also known as ADRA1B, is an alpha-1 adrenergic receptor, and also denotes the human gene encoding it.
A lead compound (i.e. a "leading" compound, not to be confused with various compounds of the metallic element lead) in drug discovery is a chemical compound that has pharmacological or biological activity likely to be therapeutically useful, but may nevertheless have suboptimal structure that requires modification to fit better to the target; lead drugs offer the prospect of being followed by back-up compounds.
Phendioxan is an alpha 1-adrenoreceptor antagonist.
A receptor antagonist is a type of receptor ligand or drug that blocks or dampens a biological response by binding to and blocking a receptor rather than activating it like an agonist.