SR-57227A is a potent and selective agonist at the 5HT3 receptor, with high selectivity over other serotonin receptor subtypes and good blood-brain barrier penetration. SR-57227A had affinities (IC50) varying between 2.8 and 250 nM for 5-HT3 receptor binding sites in rat cortical membranes and on whole NG 108-15 cells or their membranes in vitro. SR 57227A stimulated the uptake of [14C]guanidinium into NG 108-15 cells in the presence of substance P and contracted the isolated guinea-pig ileum, effects that were antagonized by the 5-H 3 receptor antagonist tropisetron. The agonist effect of SR 57227A was also observed in vivo, as the compound elicited the Bezold-Jarisch reflex in anesthetized rats, an effect that was blocked by tropisetron.

Harmaline is a fluorescent psychoactive indole alkaloid from the group of harmala alkaloids and beta-carbolines. It is a partially hydrogenated form of harmine. Harmaline is produced by various plants including Peganum harmala aswell as Banisteriopsis caapi. Harmaline has been investigated as an anti-cancer agent and for the treatment of dementia in rats. However, Harmaline is known to induce tremors in rats.