Alpha-2 adrenergic receptor
The alpha-2 (α2) adrenergic receptor (or adrenoceptor) is a G protein-coupled receptor (GPCR) associated with the Gi heterotrimeric G-protein. It consists of three homologous subtypes, α2A-, α2B-, and α2C-adrenergic.
Source: Wikipedia — Alpha-2 adrenergic receptor (CC BY-SA 4.0)