Eltoprazine(DU28853) is a serenic or antiaggressive agent which as an agonist at the 5-HT1A and 5-HT1B receptors and as an antagonist at the 5-HT2C receptor.

In vitro, The binding of [3H]eltoprazine to whole tissue sections was saturable and revealed an apparent dissociation constant (Kd) of 11 nM. Specific [3H]eltoprazine binding was completely displaced by 5-HT; conversely, unlabelled eltoprazine reduced [3H]5-HT binding to the levels of non-specific binding [1]. Eltoprazine evoked membrane changes that were similar to but much weaker than those induced by 5HT. Both the 5HT- and eltoprazine-evoked membrane hyperpolarizations were largely suppressed in the presence of spiperone [2].

In vivo, eltoprazine is extremely effective in suppressing dyskinesia in experimental models, although this effect was accompanied by a partial worsening of the therapeutic effect of l-dopa. Interestingly, eltoprazine was found to (synergistically) potentiate the antidyskinetic effect of amantadine. The current data indicated that eltoprazine is highly effective in counteracting dyskinesia in preclinical models [3]. Rats were chronically treated with mianserin (10 mg/kg i.p.) or eltoprazine (1 mg/kg i.p.) and were tested in the elevated plus-maze test for anxiety. Mianserin and eltoprazine displayed opposite effects in the elevated plus-maze: mianserin induced anxiolytic-like effects, while eltoprazine showed anxiogenic-like ones [4].