Riociguat

Riociguat, also known as BAY 63-2521, is a novel drug that is currently in clinical development by Bayer. It is a stimulator of soluble guanylate cyclase (sGC) . At the moment Phase III clinical trials investigate the use of riociguat as a new approach to treat two forms of pulmonary hypertension (PH) : chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH) . Riociguat constitutes the first drug of a novel class of sGC stimulators. (In Vitro) :[3H]Rauwolscine binding to α2 adrenergic receptor is reversible, stcreospccific, and saturable. [3H]Rauwolscine specifically labels both the high and low affinity states of the α2 adrenergic receptor in brain membranes. [3H]Rauwolscine also behaves as a 5-HT1A receptor agonist and this conclusion is compatible with earlier functional studies, indicating that rauwolscine (as well as yohimbine) has agonistic properties at the level of 5-HT autoreceptors. When using [3H]5-HT as a radioligand, rauwolscine is determined to have relatively high affinity for the human receptor (Ki human=14.3 nM, Ki rat=35.8 nM) . Saturation studies shows that the affinity of [3H]Rauwolscine is similar in mouse, rat, rabbit, dog (2.33-3.03 nM) except man where it is significantly higher (0.98 nM) .