ANA-12 is a low-molecular weight antagonist of tropomyosin-related kinase B (TrkB), which is the main receptor of neurotrophin brain-derived neurotrophic factor (BDNF). TrkB and BDNF are both the key mediators in the pathophysiology of several mood disorders, including anxiety and depression. ANA-12 showed direct and selective binding to TrkB and inhibited processes downstream of TrkB without altering TrkA and TrkC functions. It was shown, that mice administered ANA-12 demonstrated reduced anxiety- and depression-related behaviors on a variety of tests predictive of anxiolytic and antidepressant properties in humans.

SB-699551 is the first selective serotonin 5A receptor antagonist. SB-699551 showed an anxiolytic-like property in animal model. It demostrated efficacy against schizophrenia-like cognitive deficits and negative symptoms in rats. Blockade of 5-HT5A receptor with SB-699551 appear to be able to impair the consolidation of memory in rodents. In addition, 5-HT-induced spinal antinociception in the capsaicin and acetic acid tests was blocked by SB-699551.