Effect In Tail Suspension Test Research Articles

N-(3-((3-(trifluoromethyl)phenyl)selanyl)prop-2-yn-1-yl) benzamide induces antidepressant-like effect in mice: involvement of the serotonergic system.

Major Depressive Disorder (MDD) significantly impairs the quality of life for those affected. While the exact causes of MDD are not fully understood, the deficit of monoamines, especially serotonin and noradrenaline, is widely accepted. Resistance to long-term treatments and adverse effects are often observed, highlighting the need for new pharmacological therapies. Synthetic organic compounds containing selenium have exhibited pharmacological properties, including potential antidepressant effects. To evaluate the antidepressant-like effect of N-(3-((3-(trifluoromethyl)phenyl)selenyl)prop-2-yn-1-yl) benzamide (CF3SePB) in mice and the involvement of the serotonergic and noradrenergic systems. Male Swiss mice were treated with CF3SePB (1-50mg/kg, i.g.) and 30min later the forced swimming test (FST) or tail suspension test (TST) was performed. To investigate the involvement of the serotonergic and noradrenergic systems in the antidepressant-like effect of CF3SePB, mice were pre-treated with p-CPA (a 5-HT depletor, 100mg/kg, i.p.) or the receptor antagonists WAY100635 (0.1mg/kg, s.c., a 5-HT1A receptor antagonist), ketanserin (1mg/kg, i.p., a 5-HT2A/2C receptor antagonist), ondansetron (1mg/kg, i.p., a 5-HT3 receptor antagonist), GR110838 (0.1mg/kg, i.p., a 5-HT4 receptor antagonist), prazosin (1mg/kg, i.p., an α1-adrenergic receptor antagonist), yohimbine (1mg/kg, i.p., an α2-adrenergic receptor antagonist) and propranolol (2mg/kg, i.p., a non-selective beta-adrenergic receptor antagonist) at specific times before CF3SePB (50mg/kg, i.g.), and after 30min of CF3SePB administration the FST was performed. CF3SePB showed an antidepressant-like effect in both FST and TST and this effect was related to the modulation of the serotonergic system, specially the 5-HT1A and 5-HT3 receptors. None of the noradrenergic antagonists prevented the antidepressant-like effect of CF3SePB. The compound exhibited a low potential for inducing acute toxicity in adult female Swiss mice. This study pointed a new compound with antidepressant-like effect, and it could be considered for the development of new antidepressants.

Pre-Clinical Evaluation of Antidepressant and Antioxidant Activities of a Renowned Polyherbal Formulation

Background: India is an opulent provenance of medicinal plants used therapeutically to treat various disorders including depression. The present study was designed to scrutinize the antidepressant activity of Sharbat Ahmad Shahi (SAS) in swiss albino mice. Methods: The antidepressant activity was studied in swiss albino mice using two behavioural paradigms i.e forced swimming test (FST) and tail suspension test (TST). Sharbat ahmad shahi (6ml/kg), hydroalcoholic and aqueous extract of the ingredients of SAS (0.34mg/kg and 0.64mg/kg) respectively, was used as test drugs, Flauxatine (20mg/kg) was used as a standard drug and vehicle was distilled water (10ml/kg), orally for 14 days. Results: SAS, hydroalcoholic and aqueous extract of the ingredients of SAS produced a significant antidepressant effect in both FST and TST as they reduced the immobility time. A significant reduction in TBARS and an increased in GSH levels were observed in brains of mice exposed to FST and TST. Conclusion: The present study propound that SAS, hydroalcoholic and aqueous extract of the ingredients of SAS possess an antidepressant like effect.

D-Serine produces antidepressant-like effects in mice through suppression of BDNF signaling pathway and regulation of synaptic adaptations in the nucleus accumbens

Objectived-Serine is a crucial endogenous co-agonist of N-methyl-d-aspartate receptors (NMDARs) in the central nervous system and can affect the function of the brain derived neurotrophic factor (BDNF) system, which plays an essential role in modulating synaptic plasticity. The current study aimed to systematically evaluate the role and mechanisms of d-serine in depressive behavior in nucleus accumbens (NAc).Methodsd-Serine concentration in the chronic social defeat stress (CSDS) model in NAc was measured using high-performance liquid chromatography (HPLC). The antidepressant-like effects of d-serine were identified using forced swim test (FST) and tail suspension test (TST) in control mice and then assessed in CSDS model. We applied social interaction and sucrose preference tests to identify the susceptibility of CSDS model. Western blotting was further performed to assess the changes of BDNF signaling cascade in NAc after CSDS and d-serine treatment. The BDNF signaling inhibitor (K252a) was also used to clarify the antidepressant-like mechanism of d-serine. Moreover, d-serine effects on synaptic plasticity in NAc were investigated using electrophysiological methods.Resultsd-Serine concentration was decreased in depression susceptible mice in NAc. d-Serine injections into NAc exhibited antidepressant-like effects in FST and TST without affecting the locomotor activity of mice. d-Serine was also effective in CSDS model of depression. Moreover, d-serine down-regulated the BDNF signaling pathway in NAc during CSDS procedure. Furthermore, BDNF signaling inhibitor (K252a) enhanced the antidepressant effects of d-serine. We also found that d-serine was essential for NMDARs-dependent long-term depression (LTD).Conclusiond-Serine exerts antidepressant-like effects in mice mediated through restraining the BDNF signaling pathway and regulating synaptic plasticity in NAc.

Loganin ameliorates depression-like behaviors of mice via modulation of serotoninergic system.

Depression is a serious neuropsychiatric disorder, which is characterized by sustaining mood disorders. Loganin, a major iridoid glycoside from Corni fructus, has a variety of pharmacological activities, including neuroprotective effect and hypnotic effect. However, little is known about the effects of loganin on stress-induced depression. To investigate the effects of loganin on behavioral despair of mice, and whether serotonin (5-HT) and/or noradrenaline (NE) are involved in this process. We tested the effectiveness of loganin using tail suspension test (TST). The possible mechanism was explored using reserpine-induced ptosis and hypothermia, and 5-HTP-induced head-twitch response in mice. The changes of 5-HT and NE in the prefrontal cortex, hippocampus, and striatum were measured through high-performance liquid chromatography (HPLC) analysis. Then, we identified the effects of depleting 5-HT and NE by PCPA (p-chlorophenylalanine) and DSP-4 (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride) pretreatment, respectively. Loganin (12.5/50mg/kg) induced antidepressant-like effects in mice submitted to TST. Loganin (12.5/50mg/kg) ameliorated the reserpine-induced hypothermia and ptosis, as well as increased 5-HTP-induced head-twitch responses in mice. Loganin (50mg/kg) significantly increased the levels of 5-HT in the prefrontal cortex, hippocampus, and striatum. Furthermore, only PCPA treatment could eliminate loganin-induced antidepressant-like effects in TST. Loganin exerts antidepressant-like effect in the TST depending on 5-HT levels in the central nervous system, which provide a potential agent for depression therapy.

Opioid receptor system contributes to the acute and sustained antidepressant-like effects, but not the hyperactivity motor effects of ketamine in mice

In 2000, a subanesthetic dose (0.5 mg/kg i.v.) of the dissociative anesthetic ketamine was reported to have both rapid and robust antidepressant effects in patients diagnosed with major depressive disorder and later, ketamine also was shown to be effective in treatment-resistant depressed patients. However, the mechanisms responsible for ketamine's antidepressant effects remain unclear. In 2018, a clinical study reported that pretreatment with the nonselective opioid antagonist naltrexone attenuated the rapid antidepressant effect of ketamine in depressed patients. The current study investigated the potential role of the opioid receptor system in the acute and sustained antidepressant-like and hyperactive effects of ketamine. Mice were tested in the tail suspension test (TST) and differential-reinforcement-of-low-rate responding (DRL) 72 s task which are behavioral screens for antidepressant-like properties. Additionally, open field locomotor activity also was measured. In all behavioral assays, mice were pretreated with the nonselective opioid receptor antagonist naltrexone or saline prior to ketamine administration. The current study found that ketamine (10 mg/kg) produced acute (30 min) and sustained (24 h) antidepressant-like effects in TST, which were attenuated by pretreatment of 2 mg/kg naltrexone. Ketamine (32 mg/kg) also produced an acute antidepressant-like effect in the DRL 72 s task that was attenuated by pretreatment of 2 mg/kg naltrexone. Finally, ketamine (10 and 32 mg/kg) produced hyperactivity in the open field; however, pretreatment with 2 mg/kg naltrexone failed to block the hyperactivity effects ketamine. These results, along with recent clinical findings, suggest that ketamine's antidepressant effects, but not its hyperactive effects, involve activation of the opioid system.

Ketamine; A better anti-depressant? An animal study evaluating the efficacy of citalopram, ketamine and their combination in animal models of depression

Background: Despite the availability of vast group of drugs, treatment of depression still remains unsatisfactory, largely due to differential efficacy of antidepressants at adequate doses resulting in treatment refractive depression. In addition, serious adverse effects of anti-depressants also lead to early withdrawal from treatment. One more important concern is the therapeutic lag of nearly 3-4 weeks, before some appreciable clinical effect. Therefore, newer agents with good safety profile, rapid onset of action and with substantial benefits in treating patients who are either refractory or resistant to conventional therapy, need to be explored. Methods: 8 groups of 6 mice each were evaluated for anti-depressant effect in Tail Suspension Test and Forced Swim Test. Treatment used was normal saline (control), citalopram, ketamine and combination of ketamine with citalopram. Results: Citalopram decreased the immobility time in both models but it was not significant in FST. Significant decrease in immobility time was observed in ketamine treated mice in both models. Ketamine and citalopram combination also decreased the immobility time significantly. Conclusion: Ketamine have an antidepressant activity of its own, as shown in both TST & FST models. Additionally, it also potentiated the antidepressant effect of citalopram, which could be attributed to possible involvement of NMDA receptors and its interaction with the monoaminergic system.

Assessment of the rapid and sustained antidepressant-like effects of dextromethorphan in mice

The glutamatergic system has emerged as a novel pathway for treating major depressive disorder (MDD) with the focus on producing both rapid and sustained antidepressant effects. Dextromethorphan is a noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist that has produced antidepressant-like effects in forced swim and tail suspension tests (TST); however, the rapid and sustained antidepressant-like effects of dextromethorphan have not been evaluated. This study evaluated the rapid and sustained (24 h) antidepressant-like effects of dextromethorphan (0–32 mg/kg) in C56BL/6 mice using the novelty-induced hypophagia (NIH) test and TST, respectively. Additionally, we evaluated anxiety-related behavior and locomotor effects of dextromethorphan (0–56.0 mg/kg) using the light-dark and open field tests. Dextromethorphan (32 mg/kg) produced acute (30 min) antidepressant-like effects in TST, but failed to produce antidepressant-like effects 24 h after drug administration. Treatment of dextromethorphan (32 mg/kg) alone or in combination with CYP2D6 enzyme inhibitor Quinidine (32 mg/kg) failed to produce rapid antidepressant-like effects by increasing the latency to drink in the NIH test rather than decreasing the latency to drink. Dextromethorphan (56 mg/kg) produced an anxiogenic-like effect by decreasing the time spent in the light side, number of entries, and latency to enter the light side in the light-dark test. Administration of dextromethorphan (0–56 mg/kg) did not significantly alter locomotor activity. Although dextromethorphan is considered a noncompetitive NMDA receptor antagonist, dextromethorphan binds to several monoaminergic receptors (SERT and NET) and likely produces the antidepressant-like effects through these receptors similar to traditional antidepressant drugs. Additionally, these results suggest that the therapeutic window for dextromethorphan in the clinical population is small as similar doses produce antidepressant-like and anxiogenic-like behaviors.

Effect of vitamin D on depression: an experimental study

Background: There is a scarcity of studies regarding antidepressant activity of vitamin D in animals while there are some contradictory reports regarding the same in humans. Therefore the present study was planned to investigate the antidepressant effect of vitamin D and its interaction with standard antidepressant drugs in animals.Methods: Forced swim test (FST) in adult male Wistar rats and tail suspension test (TST) in adult male Swiss albino mice were used to investigate antidepressant activity of vitamin D administered in single dose and multiple doses. Imipramine, a tri-cyclic antidepressant and fluoxetine, a selective serotonin reuptake inhibitor were used as standard antidepressant drugs. For interaction studies, half the therapeutic equivalent dose of vitamin D was combined with sub-effective dose (SED) of imipramine or fluoxetine. Data was expressed as Mean±SD and analyzed by standard statistical tests. P<0.05= significant. Present study was ethically approved.Results: Single dose administration of vitamin D did not show significant antidepressant effect either in FST or TST. Multiple dose administration of vitamin D showed significant antidepressant activity in TST but not in FST. Combination of vitamin D (half dose) with SED of either standard antidepressant drugs did not show any significant antidepressant activity. None of the treatment groups showed any significant difference on locomotor activity.Conclusions: In the present study, multiple dose administration of vitamin D showed some antidepressant activity. Further studies are needed to confirm and elaborate the role of vitamin D in behavioral disorders like depression.

Reversal effect of Riparin IV in depression and anxiety caused by corticosterone chronic administration in mice

Mental disorders have a multifactorial etiology and stress presents as one of the causal factors. In depression, it is suggested that high cortisol concentration contributes directly to the pathology of this disease. Based on that, the study aims to evaluate the potential antidepressant effect of Riparin IV (Rip IV) in mice submitted to chronic stress model by repeated corticosterone administration. Female Swiss mice were selected into four groups: control (Ctrl), corticosterone (Cort), Riparin IV (Cort + Rip IV) and fluvoxamine (Cort + Flu). Three groups were administrated subcutaneously (SC) with corticosterone (20 mg/kg) during twenty-one days, while the control group received only vehicle. After the fourteenth day, groups were administrated tested drugs: Riparin IV, fluvoxamine or distilled water, by gavage, 1 h after subcutaneous injections. After the final treatment, animals were exposed to behavioral models such as forced swimming test (FST), tail suspension test (TST), open field test (OFT), elevated plus maze (EPM) and sucrose preference test (SPT). The hippocampus was also removed for the determination of BDNF levels. Corticosterone treatment altered all parameters in behavioral tests, leading to a depressive- and anxious-like behavior. Riparin IV and fluvoxamine exhibit antidepressant effect in FST, TST and SPT. In EPM and OFT, treatment displayed anxiolytic effect without alteration of locomotor activity. Corticosterone administration decreased BDNF levels and Riparin IV could reestablish them, indicating that its antidepressant effect may be related to ability to ameliorate hippocampal neurogenesis. These findings suggest that Riparin IV improves the depressive and anxious symptoms after chronic stress and could be a new alternative treatment for patients with depression.

Evaluation of the pharmacological involvement of ATP-sensitive potassium (KATP) channels in the antidepressant-like effects of topiramate on mice.

Acute doses of topiramate (TPM) have been shown to reduce immobility time in the mice forced swimming test (FST) through inhibition of the nitric oxide (NO) pathway. Adenosine triphosphate-sensitive potassium (KATP) channels are known to have an active role in depression. This study investigates the potential participation of KATP channels in the antidepressant-like effect of TPM through the stimulatory effects of NO. FST and tail suspension tests (TST) were applied to adult male mice for assessment of the antidepressant-like activity of TPM. Different doses of glibenclamide and cromakalim were also applied in order to investigate the involvement of KATP channels. Fluoxetine was used as a positive control for evaluation of antidepressant-like effects. In addition, each animal's locomotor activity was evaluated by the open-field test (OFT). TPM (30mg/kg intraperitoneal (i.p.)) had a significant reductive effect on the immobility behavior similar to fluoxetine (20mg/kg). Co-administration of sub-effective doses of glibenclamide (1mg/kg i.p.) and TPM (10mg/kg i.p.) led to significant synergistic effects in FST and TST. Additionally, the results showed that administration of the sub-effective dose of cromakalim (0.1 and 0.3mg/kg i.p.) blocked the antidepressant-like effects of TPM (30mg/kg i.p.) in both tests. These interventions had no impact on the locomotor movement of mice in OFT. This study shows that the antidepressant-like activity of TPM may potentially be mediated by the blocking of the KATP channels.

A 28-day Sub-acute Genotoxic and Behavioural Assessment of Garcinielliptone FC.

Garcinielliptone FC (GFC) is a polyisoprenylated benzophenone isolated from Platonia insignis Mart (Clusiaceae) with promising anticonvulsant properties. However, its safe use and other effects on the central nervous system require assessment. This study assessed the toxicological effects of GFC using the comet assay and the micronucleus test in mice treated for 28 days. A behavioural model was employed to detect possible injuries on the central nervous system. Mice treated with GFC (2, 10 and 20 mg/kg; i.p.) daily for 28 days were submitted to rotarod test, open-field test and tail suspension test (TST). After the behaviour tasks, biological samples were assessed to evaluate genotoxic and mutagenic effects using the comet assay and the micronucleus test. Garcinielliptone FC did not impair the performance of the animals in the rotarod and open-field tests, with no antidepressant-like effect in TST. No genotoxic effects in blood and cerebral cortex were observable in the comet assay; however, there was a significant increase in index and frequency of damage in liver after treatment with GFC 20 mg/kg. Garcinielliptone FC did not increase micronucleus frequency in bone marrow. At the tested doses, GFC was not toxic to the CNS and did not induce genotoxic damage to blood or bone narrow cells. DNA damage to liver tissue was caused only by the highest dose, although no mutagenic potential was observed.

The antidepressant-like activity of ellagic acid and its effect on hippocampal brain derived neurotrophic factor levels in mouse depression models

The aim of present study was to evaluate the antidepressant-like activity of ellagic acid (EA) in mice-forced swim test (FST) and tail suspension test (TST) and the possible role of brain-derived neurotrophic factor (BDNF) in EA’s antidepressant-like effect. We found that EA and sertraline did not affect the spontaneous locomotor activity of mice. EA produced statistically significant decrease in immobility time as compared to vehicle group in TST. EA at 1 and 5 mg/kg doses did not produce any significant effect in immobility time as compared to vehicle group in FST. But EA produced significantly reduced immobility time at 2.5 mg/kg dose. EA treatment increased hippocampal BDNF level. This study demonstrates that EA is able to produce antidepressant-like effect in both TST and FST in mice. Moreover, the antidepressant-like effects of EA seems to be mediated by increased BDNF level in mice hippocampus.

Neuropharmacological and acute toxicological evaluation of ethanolic extract of Allamanda cathartica L. flowers and plumieride

Psychiatric diseases affect more than 350 million people all over the world, and medicinal plants have been considered the basis for pharmacological research. The study investigates the anticonvulsant and antidepressant-like activities and acute toxicological effects of ethanolic extract of Allamanda cathartica flowers, and plumieride. The extract was analyzed by HPLC and plumieride was isolated. Toxicity studies were carried out on females Wistar rats (2000 mg/kg). Toxicity was evaluated by measuring biochemical parameters and conducting histopathological analysis. For pharmacological evaluation different doses of the extract (100, 150 and 300 mg/kg, p.o.) and plumieride (0.5, 1 and 2 μg/kg, i.p.) were administered before the Forced-Swimming Test (FST), pentylenetetrazole seizure test (PTZT) or Tail-Suspension Test (TST) in mice. Furthermore, hemolytic activity, cytotoxicity and micronucleus test were performed. In addition, mutagenicity and reproductive/developmental toxicity were estimated by TEST-software analysis. Data show that both treatments induce significant antidepressive-like effect in FST and TST, but not anticonvulsant effect. The effect of plumieride last up to 4 h after treatment. No signs of toxicity, mutagenicity, cytotoxicity or hemolytic activity were observed. The TEST-software demonstrated that plumieride present reproductive/developmental toxicity. Together, the data obtained show that the flowers extract and plumieride present antidepressant-like effect and did not present signals of acute toxicity.

The role of neuropeptide-Y in nandrolone decanoate-induced attenuation of antidepressant effect of exercise.

Since the increased prevalence of anabolic androgenic steroids abuse in last few decades is usually accompanied by various exercise protocols, the scope of our study was to evaluate the effects of chronic nandrolone decanoate administration in supraphysiological dose and a prolonged swimming protocol (alone and simultaneously with nandrolone decanoate) on depressive state in male rats. Simultaneously, we investigated the possible alterations in neuropeptide Y (NPY) content in blood and the hippocampus, in order to determine the role of NPY in the modulation of depressive-like behavior.Exercise induced antidepressant effects in tail suspension test (decrease of the total duration of immobility), as well as significant increase in the number of hippocampal NPY-interneurons in CA1 region. Chronic nandrolone decanoate treatment attenuated the beneficial antidepressant effects of exercise as measured by the tail suspension test parameters. Simultaneously, nandrolone decanoate treatment resulted in diminution of NPY content both in blood (decreased serum levels) and in hippocampus (the significant decrease in NPY expression in all three investigated hippocampal regions—CA1, CA2/3 and DG). Our findings indicate that alterations in serum and hippocampal NPY contents may underlie the changes in depressive state in rats. The exercise was beneficial as it exerted antidepressant effect, while chronic nandrolone decanoate treatment resulted in depressive-like behavior. Furthermore, the behavioral indicators of depression showed strong correlations with the serum levels and the hippocampal content of NPY.

Alterations of the oxidative status in rat hippocampus and prodepressant effect of chronic testosterone enanthate administration.

In a last few decades, anabolic-androgenic steroids (AASs) abuse has become serious health concern especially among adolescents. AASs abuse has been reported to be involved in pathogenesis of various mood disorders, including depression. In order to evaluate the effects of chronic (6weeks) testosterone enanthate (TE) treatment in supraphysiological dose and exercise on depression-like behavior in rats, 32 male rats were divided into four groups: control (C), testosterone enanthate (T, 20mg/kg/w, s.c.), exercise (E, swimming for 1h/day), and combined group-testosterone enanthate plus exercise (T + E). TE produced prodepressant effect in tail suspension test (TST) parameters compared to the control and exercise groups, while exercise induced the opposite effect. Simultaneous TE administration along with exercise attenuated the antidepressant effect of exercise reversing the parameters of TST to the control values. Oxidative stress markers in rat hippocampus were significantly altered following applied protocols. TE administration increased index of lipid peroxidation (TBARS) and decreased superoxide dismutase activity (SOD), while exercise induced the opposite effect, with no change in glutathione (GSH) levels. Our results indicate that TE chronic treatment resulted in clear depressive-like behavior, even abolishing beneficial antidepressant effects of exercise in TST that was accompanied with increased oxidative damage in rat hippocampus. The antidepressant effect of exercise correlated with the improvement of redox status in hippocampal tissue. Behavioral parameters obtained in TST significantly correlated with the levels of oxidative stress markers.

Cacna1c in the Prefrontal Cortex Regulates Depression-Related Behaviors via REDD1.

The CACNA1C gene that encodes the L-type Ca2+ channel (LTCC) Cav1.2 subunit has emerged as a candidate risk gene for multiple neuropsychiatric disorders including bipolar disorder, major depressive disorder, and schizophrenia, all marked with depression-related symptoms. Although cacna1c heterozygous (HET) mice have been previously reported to exhibit an antidepressant-like phenotype, the molecular and circuit-level dysfunction remains unknown. Here we report that viral vector-mediated deletion of cacna1c in the adult prefrontal cortex (PFC) of mice recapitulates the antidepressant-like effect observed in cacna1c HET mice using the sucrose preference test (SPT), forced swim test (FST), and tail suspension test (TST). Molecular studies identified lower levels of REDD1, a protein previously linked to depression, in the PFC of HET mice, and viral-mediated REDD1 overexpression in the PFC of these HET mice reversed the antidepressant-like effect in SPT and TST. Examination of downstream REDD1 targets found lower levels of active/phosphorylated Akt (S473) with no change in mTORC1 phosphorylation. Examination of the transcription factor FoxO3a, previously linked to depression-related behavior and shown to be regulated in other systems by Akt, revealed higher nuclear levels in the PFC of cacna1c HET mice that was further increased following REDD1-mediated reversal of the antidepressant-like phenotype. Collectively, these findings suggest that REDD1 in cacna1c HET mice may influence depression-related behavior via regulation of the FoxO3a pathway. Cacna1c HET mice thus serve as a useful mouse model to further study cacna1c-associated molecular signaling and depression-related behaviors relevant to human CACNA1C genetic variants.

Involvement of nitric oxide-cyclic guanosine monophosphate pathway in the antidepressant-like effect of tropisetron and ondansetron in mice forced swimming test and tail suspension test

Antidepressant-like effects of 5-hydroxytryptamine subtype 3 (5-HT3) antagonists including tropisetron and ondansetron have been previously demonstrated in the literature. It was reported that stimulation of 5-HT3 receptors activate the nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway, which is involved in regulation of behavioral and emotional functions. In our study, treating animals with tropisetron (5, 10, and 30mg/kg) and ondansetron (0.01 and 0.1µg/kg) significantly decreased the immobility time in forced swimming test (FST) and tail-suspension test (TST). Co-administration of subeffective doses of tropisetron (1mg/kg) and ondansetron (0.001µg/kg) with subeffective dose of l-NAME (10mg/kg, nonselective NO synthase (NOS) inhibitor) and 7-nitroindazole (25mg/kg, neural NOS inhibitor) exerted antidepressant-like effect in FST and TST, while aminoguanidine (50mg/kg, inducible NOS inhibitor) did not enhance the antidepressant-like effect of 5-HT3 antagonists. Besides, l-arginine (750mg/kg, NO precursor) and sildenafil (5mg/kg, phosphodiesterase inhibitor) suppressed the anti-immobility effect of 5-HT3 antagonists. None of the treatments altered the locomotor behavior of mice in open-field test. Also, hippocampal (but not cortical) nitrite level was significantly lower in tropisetron and ondansetron-treated mice compared with saline-injected mice. Also, co-administration of 7-nitroindazole with tropisetron or ondansetron caused a significant decrease in hippocampal nitrite levels. In conclusion, we suggest that antidepressant-like effect of tropisetron and ondansetron are partially mediated by modulation of NO-cGMP pathway.

Antidepressant- and anxiolytic-like effect of novel 5-hydroxytryptamine3 receptor antagonist 2-[4-(3-chlorophenyl) piperazin-1-yl]-1,8-naphthyridine -3-carboxylic acid (7e)-: An approach using rodent behavioral antidepressant and anxiolytic test battery

Aim: Depression and anxiety are among the most common and prevalent forms of mental disorder. The 5-hydroxytryptamine3 (5-HT 3 ) receptor antagonists modulate serotonergic pathways and show antidepressant- and anxiolytic-like effect in various animal models of depression. The present study was designed to investigate the antidepressant and anxiolytic potential of 2-[4-(3-chlorophenyl) piperazin-1-yl]- 1,8-naphthyridine-3-carboxylic acid (7e), a novel 5-HT 3 receptor antagonist in rodent behavioral models of depression and anxiety. Materials and Methods: The compound 7e was tested using different behavioral models for depression and anxiety such as forced swim test (FST), tail suspension test (TST), mechanistic models such as 5-hydroxytryptophan (5-HTP)-induced head twitch, elevated plus maze (EPM), hole-board (HB) test, open field test (OFT), and light and dark (L and D) aversion test. Results: The compound 7e (1 and 2 mg/kg, intraperitoneally [i.p.]) exhibits antidepressant-like effect in FST. In addition, compound 7e (0.5, 1 and 2 mg/kg, i.p.) exhibits antidepressant-like effect in TST after acute treatment without any significant effect on base line spontaneous locomotor activity. Moreover, compound 7e (2 mg/kg, i.p.) potentiated the 5-HTP-induced head twitch responses in mice. In interaction studies, compound 7e (0.5 mg/kg, i.p.) potentiated the antidepressant effect of bupropion. Furthermore, compound 7e also exhibited anxiolytic-like effect in EPM, HB test, OFT, and L and D aversion test. Conclusion: These preliminary studies reveal that compound 7e exhibits antidepressant- and anxiolytic-like effect in behavioral rodent models of depression and anxiety.

Involvement of monoaminergic system in the antidepressant-like effect of (octylseleno)-xylofuranoside in the mouse tail suspension test

Depression is one of the most commonly diagnosed neuropsychiatric disorders and several studies have demonstrated a role for selenium in mood disorders. For this reason, the present study investigated the role of the monoaminergic system in the antidepressant-like action of (octylseleno)-xylofuranoside (OSX), an organoselenium compound, in the tail suspension test (TST) in mice. For this purpose, OSX (0.001–10mg/kg) was administered orally (p.o.) 30min prior to testing, and all of the tested doses reduced the immobility time in the TST without changing the locomotor activity measured in the open field test (OFT). Furthermore, the antidepressant-like effect of OSX (0.01mg/kg, p.o.) in the TST was prevented by pre-treatment in mice with ketanserin (1mg/kg, intraperitoneal route (i.p.); a 5-HT2A/2C receptor antagonist), WAY100635 (0.1mg/kg, subcutaneous (s.c.); a selective 5-HT1A receptor antagonist), p-chlorophenylalanine methyl ester-PCPA (100mg/kg, i.p.; a selective inhibitor of tryptophan hydroxylase), prazosin (1mg/kg, i.p.; an α1-adrenoceptor antagonist), yohimbine (1mg/kg, i.p.; an α2-adrenoceptor antagonist), SCH233390 (0.05mg/kg, s.c., a dopaminergic D1 receptor antagonist) and sulpiride (50mg/kg, i.p., a dopaminergic D2 receptor antagonist), but not with ondansetron (1mg/kg, i.p.; a selective 5-HT3 receptor antagonist). Taken together, these data demonstrate that OSX has a potent antidepressant-like effect in TST at lower doses (0.001–10mg/kg), which is dependent on its interaction with the serotonergic, noradrenergic and dopaminergic systems.

Evidence for the involvement of NMDA receptors in the antidepressant-like effect of nicotine in mouse forced swimming and tail suspension tests.

The antidepressant action of acute nicotine administration in clinical and animal studies is well recognized. But the underlying mechanism for this effect has not been carefully discovered. We attempted to evaluate the possible role of N-Methyl-D-aspartate (NMDA) receptors in the antidepressant-like effect of nicotine. After the assessment of locomotor activity in the open-field test, forced swimming test (FST) and tail suspension test (TST) were used to evaluate the antidepressant-like effect of nicotine in mice. We performed intraperitoneal administration of nicotine at different doses and periods before the tests. To assess the possible involvement of NMDA receptors, non-effective doses of NMDA antagonists and an NMDA agonist were obtained and were administered simultaneously with the non-effective and effective doses of nicotine, respectively. Nicotine (0.2mg/kg, 30min before FST/TST) significantly reduced the immobility time of mice similar to fluoxetine (20mg/kg). Nicotine did not affect the locomotor behavior of mice in open-field test. Co-administration of non-effective doses of NMDA receptor antagonists, ketamine (1 or 0.3mg/kg), MK-801 (0.05 or 0.005mg/kg), and magnesium sulfate (10 or 5mg/kg) with nicotine (0.1 or 0.03mg/kg) had remarkable synergistic antidepressant effect in both FST and TST. Also, non-effective NMDA (75 or 30mg/kg) reversed the anti-immobility effect of nicotine (0.2mg/kg) on mouse FST and TST. Our study has for the first time confirmed that the antidepressant-like effect of nicotine on mice is NMDA-mediated, and nicotine presumably exerts this effect by antagonizing the glutamatergic NMDA receptors.