5-HT6 receptor ligands, EMD386088 and SB258585, differentially regulate 5-HT6 receptor-independent events

► Serotonin is a key neurotransmitter in cognition and mood disorder. ► Many animal studies report conflicting results for 5-HT6R ligands. ► We investigate effects of 5-HT6R ligands using several in vitro assays. ► 5-HT6R ligands produce cell toxicity but different cellular effects. ► In vitro assays for newly developing chemicals will help interpret in vivo conflicting results.