Does the serenic eltoprazine have antidepressant potential? - An investigation in three rodent paradigms

Several novel antidepressants have a high affinity for 5-HT₁ and 5-HT₂ receptors. The recently developed serenic eltoprazine is a partial agonist at the 5-HT(1A) and 5-HT(1B) receptors and an antagonist of the 5-HT(2C) receptor subtype and is thus of interest as an antidepressant. These subtypes have been implicated in the pathogenesis of depression. The objective of this study was to appraise the antidepressant potential of eltoprazine (1 mg kg^-1 i.p.) in three tests which are indicative of antidepressant activity, namely: (1) the forced swim test, following sub-acute administration; (2) 'open field' activity in the olfactory bulbectomised (OB) rat, following chronic (14 day) administration; and (3) 8-OH-DPAT-induced hypothermia following chronic (16 day) treatment. Eltoprazine did not reduce the immobility time in either the sham or OB groups as compared with their respective controls. In the 'open field' test, chronic eltoprazine treatment did not attenuate the characteristic OB-induced hyperactivity, neither did it reverse the hypothermia induced by an acute challenge of 8-OH-DPAT. It can be concluded that eltoprazine. at the dose employed in these animal models, does not display putative antidepressant properties.