The effect of nitrazepam on depression and curiosity in behavioral tests in mice: The role of potassium channels

Role of Multifaceted Social Relationships on the Association of Loneliness with Depression Symptoms: A Moderated Mediation Analysis

Strong relationship exists between loneliness and depression in older adults. However, the effect of multifaceted social relationships on the relationship between loneliness and depression has not been explored. The purpose of the current study was to find out how multifaceted social relationships affect the aforementioned processes. We investigated and evaluated the loneliness status, depression symptoms, social relationships, and demographic information of 1116 older adults aged ≥65 years living in rural Japan. The final 555 participants were included in the analysis. Statistical evidence showed a direct effect between loneliness and depression symptoms. Additionally, the mediation model found that social curiosity and participation acted as mediators between loneliness and depression symptoms. Further, independence and participation, independence, and feeling safe played a conditional moderating role in the model of loneliness-social curiosity-depression symptoms and loneliness-participation-depression symptoms, respectively. Interaction can be an individual moderator in the link between loneliness and depression symptoms without any mediator. The moderated mediation model suggests that social curiosity and participation could mediate the association between loneliness and depression symptoms. In this process, independence, participation, and feeling safe may act as moderators.

Separation and purification of magnoflorine, spinosin, and 6‴-feruloyspinosin from Ziziphi Spinosae Semen by high-speed counter-current chromatography

In the study, high-speed counter-current chromatography was used for separation and purification of magnoflorine, spinosin, and 6‴-feruloyspinosin from Ziziphi Spinosae Semen. With n-butanol-ethyl acetate-water (2:3:5, v/v) as the optimum solvent system, about 75 mg of magnoflorine, 110 mg of spinosin, and 40 mg of 6‴-feruloyspinosin were isolated from 0.5 g of crude extract of Z. Spinosae Semen, with the purity of 95.7, 97.2, and 96.4%, respectively. The chemical structures were identified by MS and NMR spectroscopy. In addition, the antidepressant activity of the isolated components was evaluated by PC12 cells injury model and chronic unpredictable mild stress depression mouse model. The results showed that high-speed counter-current chromatography could be used to realize the one-time rapid preparation and separation of magnoflorine, spinosin, and 6‴-feruloyspinosin from Z. Spinosae Semen and compatibility of these isolated components has certain antidepressant activity.

Antidepressant-like effect of ethanol in mice forced swimming test is mediated via inhibition of NMDA/nitric oxide/cGMP signaling pathway

There is evidence for a dramatic relationship between depression and alcohol consumption. Depressed patients may abuse ethanol because this agent reduces the symptoms of depression. In the current study, we aimed to investigate the NMDA/nitric oxide/cGMP pathway in the antidepressant-like effect of ethanol in an animal model of behavioral despair. Animals were subjected to locomotor activity in an open-field test separately, followed by a forced swimming test. During the forced swimming test (FST), ethanol (2 and 2.5 g/kg) significantly decreased the immobility time without altering the locomotor activity of animals. The antidepressant-like effect of ethanol (2.5 g/kg) was reversed by co-administration of N-methyl-D-aspartate (NMDA, 75 mg/kg), L-arginine (750 mg/kg), or sildenafil (5 mg/kg). In contrast, co-administration of MK-801 (0.05 mg/kg), ketamine (1 mg/kg), and ifenprodil (0.5 mg/kg) as antagonists of NMDAR, and NG-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg), 7-nitroindazole (7-NI, 30 mg/kg), and methylene blue (10 mg/kg) as inhibitors of nitric oxide synthase (NOS), or 1H-[1,2,4]oxadiazole[4,3-a]quinoxalin-1-one (ODQ) (20 mg/kg), a nitric oxide/cyclic-guanosine monophosphate (NO-cGMP) inhibitor, with a subeffective dose of ethanol (1.5 g/kg), significantly decreased the immobility time in the FST. Furthermore, injection of ethanol 2.5 g/kg alone or 1.5 g/kg with a 7-NI subeffective dose, significantly decreased the nitrite levels in the hippocampus and prefrontal cortex. Hence, it is concluded that blockade of NMDA receptors and the nitric oxide/cyclic-guanosine monophosphate (NO-cGMP) pathway might be involved in the antidepressant-like effect of ethanol in mice.

Effect of adzuki bean sprout fermented milk enriched in γ-aminobutyric acid on mild depression in a mouse model

This study focused on the ability of adzuki bean (Vigna angularis) sprout fermented milk, which is rich in γ-aminobutyric acid (GABA), to relieve anxiety and mild depression. A high-yield GABA-producing strain, Lactobacillus brevis J1, from a healthy cow was screened, and its physiological and probiotic properties were evaluated. The effect of adzuki bean sprout fermented milk was investigated in vivo in a chronic depression mouse model. The results showed that Lb. brevis J1 had excellent probiotic properties, grew well at low pH and 3% NaCl, and adhered to the surface of HT-29 cells. The GABA-enriched (241.30 ± 1.62 µg/mL) adzuki bean sprout fermented milk prepared with Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus plantarum, and Lb. brevis J1 can reduce and possibly prevent mild depression-like symptoms in mice (C57/B6) by increasing social interaction and enhancing the pleasure derived from movement. The research revealed that the GABA_B-cyclic AMP-protein kinase A-cAMP-response element binding protein (GABA_B-cAMP-PKA-CREB) signaling pathway was related to the depression-like symptoms and that levels of 5-hydroxytryptamine, norepinephrine, and dopamine in the hippocampus of mice increased after treatment with the adzuki bean sprout fermented milk. Our results suggest that GABA-enriched dairy products have the potential to prevent or treat mild depression-like symptoms in mice, which suggests a new approach for a dietary therapy to treat chronic social stress.

Psychotropic Effects of a New Pyrazolo[C]Pyridine Derivate GIZh-72 are Related to Functional Activity of Atp-Sensitive Potassium Channels

We studied the influence of intraperitoneal injection of ATP-sensitive potassium channels inhibitor glibenclamide in doses of 0.01, 0.1, 1, and 10 mg/kg on the effects of a new pyrazolo[C]pyridine derivative GIZh-72 (4,6-dimethyl-2-(4-chlorphenyl)-2,3-dihydro-1Hpyrazolo[ 4,3-C]pyridine-3-on, chloral hydrate; 20 mg/kg, intraperitoneally) in the marble burying and open-field tests in mice. It was found that glibenclamide produced an anxiolytic effect in the open-field test (in a dose of 0.01 mg/kg) and anticompulsive effect in the marble burying test (in doses of 1 and 10 mg/kg). The observed behavioral effects of glibenclamide did not depend on blood glucose level. At the same time, glibenclamide in subeffective (0.01 and 0.1 mg/kg) and effective (1 and 10 mg/kg) doses potentiated the psychotropic effects of GIZh-72 in these tests. It can be assumed that the psychotropic effects of GIZh-72 depend on functional activity of ATP-sensitive potassium channels.

Revisiting the validity of the mouse tail suspension test: Systematic review and meta-analysis of the effects of prototypic antidepressants

Animal models in neuropsychiatric research need validation. One way to address external validity is systematic reviews and meta-analyses. The present study presents a meta-analysis of the effects of antidepressants in the mouse tail suspension test (TST). A PubMed search identified studies that examined imipramine and fluoxetine effects in the TST. Inclusion criteria were testing in the light phase; trial duration was six minutes; immobility time scored 6 or (last) 4 min; adult mice; acute intraperitoneal (IP) administration. Effect sizes (ES) were estimated using Cohen's d, heterogeneity of ES with Cochran's Q test, correlations between dose and ES with Pearson's correlation and differences between strains with Analysis of variance. Results show that antidepressants decrease immobility time in the TST and a correlation between drug dose and ES but no effects of strain. We suggest that the TST is a valid tool to quantitatively, consistently and reproducibly capture the immobility-reducing aspects of fluoxetine and imipramine and that the lack of strain effects is due to small number of experiments in many of the strains.

Use of magnoflorine-phospholipid complex to permeate blood-brain barrier and treat depression in the CUMS animal model

To improve the liposolubility and blood-brain barrier permeability of magnoflorine, a new formulation of magnoflorine-phospholipid complex was prepared, characterized, and pharmacologically evaluated in the chronic unpredictable mild stress animal model. In this paper, the magnoflorine-phospholipid complex was synthesized and its characterization was determined. The antidepressant-like and antioxidant activity of magnoflorine-phospholipid complex was investigated by behavioral tests and western blotting analysis. As a result, the magnoflorine-phospholipid complex displayed high encapsulation efficiency and significantly improved the oil-water participate coefficient. In vivo blood-brain distribution study, the magnoflorine-phospholipid complex extended the duration of magnoflorine in blood and help magnoflorine to permeate the blood-brain barrier into brain. In behavioral tests, the magnoflorine-phospholipid complex significantly decreased immobility time compared to model control group in both FST and TST. Furthermore, the magnoflorine-phospholipid complex increased the expression of antioxidative stress-related proteins by the western blotting analysis. These findings strongly suggest that the phospholipid complex could significantly improve liposolubility, drug properties of magnoflorine and help magnoflorine permeate blood-brain barrier and exert the antidepressant effect.

Nitric oxide involvement in additive antidepressant-like effect of agmatine and lithium in mice forced swim test

Lithium is still the main agent in the management of mood disorders such as depression. Likewise, agmatine protects the central nervous system (CNS) against depression. The aim of the present study was to examine the possible additive antidepressant-like effect of agmatine and lithium in mice forced swim test (FST) as well as exploration of the probable involvement of nitric oxide (NO) pathway in this response. Results showed that pretreatment with a subeffective dose of agmatine (0.01 mg/kg) augmented the antidepressant-like effect of lithium subeffective dose (3 mg/kg) (P < 0.001). L-NG-nitroarginine methyl ester (L-NAME, nonspecific nitric oxide synthase [NOS] inhibitor) at doses of 10 and 30 mg/kg, and 7-nitroindazole (7-NI, neuronal NOS inhibitor) at doses of 15 and 30 mg/kg potentiated the antidepressant-like effect of the subeffective combination of lithium (3 mg/kg) and agmatine (0.001 mg/kg) (P < 0.001, P < 0.01, respectively). However, various doses of aminoguanidine (25 and 50 mg/kg, inducible NOS inhibitor) failed to alter the immobility time of the same combination (P > 0.05). Moreover, pretreatment with subeffective doses of L-arginine (substrate for NOS, 300 and 750 mg/kg) reversed the augmenting antidepressant-like effect of agmatine (0.01 mg/kg) on lithium (3 mg/kg) (P < 0.001). Our results revealed that agmatine enhances the antidepressant-like effects of lithium and the NO pathway might mediate this phenomenon. In addition, constitutive NOS plays a dramatic role in this response.

The role of nitric oxide-cGMP pathway in selegiline antidepressant-like effect in the mice forced swim test

BACKGROUND

Considering the pivotal role of nitric oxide (NO) pathway in depressive disorders, the aim of the present study was to investigate the antidepressant-like effect of selegiline in mice forced swimming test (FST), and possible involvement of NO-cyclic guanosine monophosphate (cGMP) pathway in this action.

METHODS

After assessment of locomotor activity in open-field test, mice were forced to swim individually and the immobility time of the last 4 min was evaluated. All drugs were given intraperitoneally (ip).

RESULTS

Selegiline (10 mg/kg) decreased the immobility time in the FST similar to fluoxetine (20 mg/kg). Pretreatment with l-arginine (NO precursor, 750 mg/kg) or sildenafil (a phosphodiesterase 5 inhibitor, 5 mg/kg) significantly reversed the selegiline anti-immobility effect. Sub-effective dose of selegiline (1 mg/kg) showed a synergistic antidepressant effect with NG-nitro-l-arginine methyl ester (L-NAME, inhibitor of NO synthase, 10 mg/kg) or 7-nitroindazole (specific neuronal NO synthase inhibitor, 30 mg/kg), but not with aminoguanidine (specific inducible NO synthase inhibitor, 50 mg/kg). Pretreatment of mice with methylene blue (an inhibitor of NO synthase and soluble guanylyl cyclase, 10 mg/kg) significantly produced a synergistic response with the sub-effective dose of selegiline. Neither of the drugs changed the locomotor activity. Also, hippocampal and prefrontal cortex (PFC) nitrite content was significantly lower in selegiline-injected mice compared to saline-administrated mice. Also, co-injection of 7-nitroindazole with selegiline produced a significant reduction in hippocampal or PFC nitrite contents.

CONCLUSIONS

It is concluded that selegiline possesses antidepressant-like effect in mice FST through inhibition of l-arginine-NO-cyclic guanosine monophosphate pathway.

Revisiting the validity of the mouse forced swim test: Systematic review and meta-analysis of the effects of prototypic antidepressants

One problem area regarding animal models for affective disorders is unclear reproducibility, including external validity or generalizability. One way to evaluate external validity is with systematic reviews and meta-analyses. The current study presents a meta-analysis of the effects of prototypic antidepressants in the mouse forced swim test (FST). We identified studies that examined effects of antidepressants in the FST in mice and used standard protocol, male mice and acute drug administration. We calculated Effect sizes using Cohen's d, homogeneity using Q statistic and correlations using Pearson's correlation. Results indicate that all drugs reduce immobility in the FST. However, effect sizes for most drugs are heterogeneous and do not show a consistent dose/response relationship across variability factors. Reducing variability by examining only one strain or data from individual laboratories partially increases dose response relationship. These findings suggest that whereas the FST is a valid tool to qualitatively screen antidepressant effects its validity in the context of hierarchical comparison between doses or compounds might be relevant only to single experiments.

The role of NMDA receptor and nitric oxide/cyclic guanosine monophosphate pathway in the antidepressant-like effect of dextromethorphan in mice forced swimming test and tail suspension test

Depression is a devastating disorder which has a high impact on the wellbeing of overall society. As such, need for innovative therapeutic agents are always there. Most of the researchers focused on N-methyl-d-aspartate receptor to explore the antidepressant like activity of new therapeutic agents. Dextromethorphan is a cough suppressant agent with potential antidepressant activity reported in mouse force swimming test. Considering N-methyl-d-aspartate as a forefront in exploring antidepressant agents, here we focused to unpin the antidepressant mechanism of dextromethorphan targeting N-methyl-d-aspartate receptor induced nitric oxide-cyclic guanosine monophosphate signaling. Dextromethorphan administered at a dose of 10 and 30mg/kg i.p significantly reduced the immobility time. Interestingly, this effect of drug (30mg/kg) was inhibited when the animals were pretreated either with N-methyl-d-aspartate (75mg/kg), or l-arginine (750mg/kg) as a nitric oxide precursor and/or sildenafil (5mg/kg) as a phosphodiesterase 5 inhibitor. However, the antidepressant effect of Dextromethorphan subeffective dose (3mg/kg) was augmented when the animals were administered with either L-NG-Nitroarginine methyl ester (10mg/kg) non-specific nitric oxide synthase inhibitor, 7-Nitroindazole (30mg/kg) specific neural nitric oxide synthase inhibitor, MK-801 (0.05mg/kg) an N-methyl-d-aspartate receptor antagonist but not aminoguanidine (50mg/kg) which is specific inducible nitric oxide synthase inhibitor as compared to the drugs when administered alone. No remarkable effect on locomotor activity was observed during open field test when the drugs were administered at the above mentioned doses. Therefore, it is evident that the antidepressant like effect of Dextromethorphan is owed due to its inhibitory effect on N-methyl-d-aspartate receptor and NO- Cyclic guanosine monophosphate pathway.