5-HT2B receptor

5-Hydroxytryptamine receptor 2B (5-HT2B) also known as serotonin receptor 2B is a protein that in humans is encoded by the "HTR2B" gene. 5-HT2B is a member of the 5-HT2 receptor family that binds the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT).
Tissue distribution and function.
The 5-HT2 receptors (of which the 5-HT2B receptor is a subtype) mediate many of the central and peripheral physiologic functions of serotonin. Cardiovascular effects include contraction of blood vessels and shape changes in platelets; central nervous system effects include neuronal sensitization to tactile stimuli and mediation of some of the effects of hallucinogenic substituted amphetamines. The 5-HT2B receptor is highly expressed in the liver and kidney, with lower levels of expression being seen in the cerebral cortex, whole brain, pancreas, and spleen. 
The 5-HT2B receptor subtype is involved in:
Clinical significance.
5-HT2B receptors have also been strongly implicated in drug-induced valvular heart disease. In this context, it is generally considered to be an antitarget.
The structure of the 5-HT2B receptor was resolved in a complex with the valvulopathogenic drug ergotamine.
Ligands.
As of 2009, few highly selective 5-HT2B receptor ligands have been discovered, although numerous potent non-selective compounds are known, particularly agents with concomitant 5-HT2C binding. Research in this area has been limited due to the cardiotoxicity of 5-HT2B agonists, and the lack of clear therapeutic application for 5-HT2B antagonists, but there is still a need for selective ligands for scientific research.
Possible applications.
5-HT2B antagonists have previously been proposed as treatment for migraine headaches, and RS-127,445 was trialled in humans up to Phase I for this indication, but development was not continued. More recent research has focused on possible application of 5-HT2B antagonists as treatments for chronic heart disease. Research claims serotonin 5-HT2B receptors have effect on liver regeneration.