Involvement of the serotonergic system in the antidepressant-like effect of 1-(phenylselanyl)-2-(p-tolyl)indolizine in mice

Abstract

Depression is a mental disorder that affects approximately 280 million people worldwide. In the search for new treatments for mood disorders, compounds containing selenium and indolizine derivatives show promising results. To evaluate the antidepressant-like effect of 1-(phenylselanyl)-2-(p-tolyl)indolizine (MeSeI) (0.5-50mg/kg, intragastric-i.g.) on the tail suspension test (TST) and the forced swim test (FST) in adult male Swiss mice and to elucidate the role of the serotonergic system in this effect through pharmacological and in silico approaches, as well to evaluate acute oral toxicity at a high dose (300mg/kg). MeSeI administered 30min before the FST and the TST reduced immobility time at doses from 1mg/kg and at 50mg/kg and increased the latency time for the first episode of immobility, demonstrating an antidepressant-like effect. In the open field test (OFT), MeSeI did not change the locomotor activity. The antidepressant-like effect of MeSeI (50mg/kg, i.g.) was prevented by the pre-treatment with p-chlorophenylalanine (p-CPA), a selective tryptophan hydroxylase inhibitor (100mg/kg, intraperitoneally-i.p. for 4days), with ketanserin, a 5-HT2A/2C receptor antagonist (1mg/kg, i.p.), and with GR113808, a 5-HT4 receptor antagonist (0.1mg/kg, i.p.), but not with WAY100635, a selective 5-HT1A receptor antagonist (0.1mg/kg, subcutaneous-s.c.) and ondansetron, a 5-HT3 receptor antagonist (1mg/kg, i.p.). MeSeI showed a binding affinity with 5-HT2A, 5 -HT2C, and 5-HT4 receptors by molecular docking. MeSeI (300mg/kg, i.g.) demonstrated low potential to cause acute toxicity in adult female Swiss mice. In summary, MeSeI exhibits an antidepressant-like effect mediated by the serotonergic system and could be considered for the development of new treatment strategies for depression.