Search

1-( m -Chlorophenyl)piperazine ( m CPP) has a fairly complex neuropsychopharmacological profile owing to its affinity to multiple serotonergic receptors. This investigation was designed to establish the effect of m CPP on rodent depression-like behaviour. m CPP was screened in a rodent behavioural test battery comprising of validated antidepressant assays and interaction studies with conventional antidepressants and ligands were carried out in forced swim and tail suspension test (in mice). m CPP (1 mg/kg, i.p.) exhibited depressant-like effects in forced swim and tail suspension test (in mice), without influencing the locomotor status. Potentiation of 5-hydroxytryptophan/pargyline induced head twitches (in mice) and hyperthermic effects (in rats) were observed at the same dose level. Further, the behavioural anomalies of the olfactory bulbectomised (OBX) rats were augmented by chronic m CPP (1–2 mg/kg) treatment as observed from the modified open field, elevated plus maze and social interaction paradigms. Interaction studies revealed that the m CPP induced depressant-like effects were reversed by ketanserin, escitalopram, amitriptyline, ziprasidone, venlafaxine pretreatments but not by bupropion, harmane, ondansetron, 8-hydroxy-2-(di- n -propylamino) tetralin (8-OH-DPAT) and MK-801. In conclusion, this study provided ample evidence that the stimulation of 5-HT 2A receptors underlies the depressogenic-like effect of m CPP. Finally, the m CPP induced depression-like behaviour in rodents is envisaged as a modified antidepressant assay to identify novel serotonergic antidepressants.

Etazolate, a pyrazolopyridine class derivative is selective inhibitor of type 4 phosphodiesterase (PDE4), an enzyme catalyzes the hydrolysis of cyclic nucleotide viz. cAMP & regulates cAMP signal transduction. Enhancing cAMP signal transduction by inhibition of PDE4 is known to be beneficial in depression disorders. Thus, the present study was designed to investigate thoroughly the antidepressant potential of etazolate using rodent behavioral models of depression. Acute treatment of etazolate (0.25–1 mg/kg, i.p.) exhibited antidepressant-like effects in forced swim test (FST) & tail suspension test (TST) in mice without influencing the baseline locomotion in actophotometer test. Interaction studies of etazolate sub-effective dose (0.12 mg/kg, i.p.), were carried out with sub-effective dose of conventional antidepressants like fluoxetine (5 mg/kg, i.p.), venlafaxine (4 mg/kg, i.p.) & desipramine (5 mg/kg, i.p.) in FST. Etazolate at sub-effective dose produced synergistic antidepressant-like effect with conventional antidepressants in the mouse FST. In addition, combined treatment of etazolate & conventional antidepressants had no significant effect on baseline locomotion. Moreover, etazolate (0.5 and 1 mg/kg, i.p.) increased head twitch scores in mice & antagonized the reserpine-induced hypothermia in rats. Chronic treatment (14 days) with etazolate (0.5 and 1 mg/kg, p.o.) & fluoxetine (10 mg/kg, p.o.) significantly reversed the behavioral anomalies induced by bilateral olfactory bulbectomy in rats in modified open field exploration. In conclusion, taken together, our results suggested that etazolate exhibited antidepressant-like activity in acute & chronic rodent models of depression & deserves as a therapeutic tool that could help the conventional pharmacotherapy of depression.