RS-127,445 is a drug which acts as a potent and selective antagonist at the serotonin

Serotonin

Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...

 5-HT_2B

5-HT2B receptor

5-hydroxytryptamine receptor 2B, also known as HTR2B, is a 5-HT2 receptor, but also denotes the human gene encoding it.-Function:...

 receptor

Receptor (biochemistry)

In biochemistry, a receptor is a molecule found on the surface of a cell, which receives specific chemical signals from neighbouring cells or the wider environment within an organism...

, with around 1000x selectivity over the closely related 5-HT_2A

5-HT2A receptor

The mammalian 5-HT2A receptor is a subtype of the 5-HT2 receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor . This is the main excitatory receptor subtype among the GPCRs for serotonin , although 5-HT2A may also have an inhibitory effect on certain areas such...

 and 5-HT_2C

5-HT2C receptor

The 5-HT2C receptor is a subtype of 5-HT receptor that binds the endogenous neurotransmitter serotonin . It is a G protein-coupled receptor that is coupled to Gq/G11 and mediates excitatory neurotransmission. HTR2C denotes the human gene encoding for the receptor, that in humans is located at the...

receptors. The role of the 5-HT_2B receptor in the body is still poorly understood, and RS-127,445 has been a useful tool in unravelling the function of the various systems in which this receptor is expressed.