Apocynin Prevents Anxiety-Like Behavior and Histone Deacetylases Overexpression Induced by Sub-Chronic Stress in Mice

Anxiety disorders are common mental health diseases affecting up to 7% of people around the world. Stress is considered one of the major environmental risk factors to promote anxiety disorders through mechanisms involving epigenetic changes. Moreover, alteration in redox balance and increased reactive oxygen species (ROS) production have been detected in anxiety patients and in stressed-animal models of anxiety. Here we tested if the administration of apocynin, a natural origin antioxidant, may prevent the anxiety-like phenotype and reduction of histone acetylation induced by a subchronic forced swimming stress (FSS) paradigm. We found that apocynin prevented the enhanced latency time in the novelty-suppressed feeding test, and the production of malondialdehyde induced by FSS. Moreover, apocynin was able to block the upregulation of p47phox, a key subunit of the NADPH oxidase complex. Finally, apocynin prevented the rise of hippocampal Hdac1, Hdac4 and Hdac5, and the reduction of histone-3 acetylation levels promoted by FSS exposure. In conclusion, our results provide evidence that apocynin reduces the deleterious effect of stress and suggests that oxidative stress may regulate epigenetic mechanisms.

Anxiolytic Effects of 8-O-Acetyl Shanzhiside Methylester on Acute and Chronic Anxiety via Inflammatory Response Inhibition and Excitatory/Inhibitory Transmission Imbalance

Anxiety leads to a global decline in quality of life and increase in social burden. However, treatments are limited, because the molecular mechanisms underlying complex emotional disorders are poorly understood. We explored the anxiolytic effects of 8-O-acetyl shanzhiside methylester (8-OaS), an active component in Lamiophlomis rotata (L. rotata; Benth.) or Kudo, a traditional herb that has been shown to be effective in the clinical treatment of chronic pain syndromes in China. Two mouse anxiety models were used: forced swimming stress (FSS)–induced anxiety and complete Freund’s adjuvant (CFA)–induced chronic inflammatory pain. All animal behaviors were analyzed on the elevated plus maze and in the open-field test. 8-OaS significantly ameliorated anxiety-like behaviors in both anxiety models and inhibited the translation enhancement of GluN2A, GluN2B, and PSD95. Moreover, a reduction in GABA receptors disrupted the excitatory/inhibitory (E/I) balance in the basolateral amygdala (BLA), indicated by increased excitatory and decreased inhibitory presynaptic release. 8-OaS also blocked microglia activation and reduced the phosphorylation of p38, c-Jun N-terminal kinase (JNK), NF-κB p65, and tumor necrosis factor alpha (TNF-α) in the BLA of anxiety mice. 8-OaS exhibits obvious anxiolytic effects by regulating the excitatory/inhibitory (E/I) synaptic transmission and attenuating inflammatory responses in the BLA.

Hepatoprotective effect of opioid peptides in stress

Introduction: Influence of the endogenous opioid system on the liver has not been studied enough. To understand the damaging effects of stress on the liver and the hepatoprotective effects of opioids, a study was performed on stress-resistant and stress-susceptible animals. Materials and methods: The investigation was performed on 725 Wistar male-rats. Various types of stress were modeled: acute immobilization stress of various duration (3, 6 and 12 hours), chronic stress of limited mobility, swimming stress and traumatic stress (resection of 70% of the liver). Agonists of various types of opioid receptors in equimolar doses were injected to stressed animals at equimolar doses: DAGO – a mu-receptor agonist – at a dose of 6.3 mcg/kg, DSLET – a delta-receptor agonist – at a dose of 10 mcg/kg, and kappa receptor agonist dynorphin A (1-13) – at a dose of 20.1 mcg/kg. Results and discussion: The stress-limiting action of the studied opioids is characterized by the reduced hepatocyte dystrophy, microcirculation correction, a decreased concentration of lipid peroxidation metabolites, a suppressed cytolytic syndrome, a stimulated synthetic ability of the liver, and is more pronounced in stress- susceptible animals. The greatest stress-protective effect is shown after administering dynorphin A (1-13) in immobilization stress, and DAGO – in swimming stress. Dynorphin A (1-13) and DAGO manifested the most pronounced effect on the liver regeneration after resection. A preliminary stress simulation accelerates liver regeneration at the initial stage after resection. Conclusion: The hepatoprotective effect of opioids in stress depends on the typological peculiarities of animals. The results obtained offer a challenge of synthesizing new hepatoprotectors.

Antidepressant-like action of diacamphe against the background stress-induced behavioral depression

Background. It was find out the cerebroprotective properties of diacamphe – (±)-cis-3-(2’-benzimidazolyl)-1,2,2-trimethylcyclopentan-carbonic acid hydrochloride in vivo experiments in the some models of brain injury. Aim. To investigate the neuroprotective and antidepressant-like activities of diacamphe. Materials and Methods. It was investigated an impact of diacamphe on inhibition of the pyramidal neurons field synaptic potentials evoked by N-methyl-D-aspartate, procedure anoxia/neuroaglicemia, and H2O2 in the electrophysiological experiments on hippocampal slices for evaluating of diacamphe neuroprotective activity. It was explored in behavioral experiments the impacts of diacamphe and antidepressant imipramine on basic manifestations of behavioral depression evoked by five-days swimming stress – helplessness and anhedonia. Results. It was ascertained in experiments on the hippocampal slices that diacamphe especially at conditions of systemic administration diminished of injury of the pyramidal neurons synapses induced by procedure anoxya/aglicemia, oxidative stress, but not N-methyl-D-aspartate action. The chronic administration of diacamphe in dose 10 mg/kg reduced the manifestations of induced by swimming stress behavioral depression, decrease duration of immobility in forced swimming test (helplessness) and increase preference of intake of sweet solution comparably with water (dilution of anhedonia). Antidepressant-like action of diacamphe differences from action of traditional antidepressant imipramine so far as diacamphe did not diminishes immobilization duration in swimming test after single administration and by more slow developing of action. Conclusions. Diacamphe possesses neuroprotective action and therefore manifests antidepressant-like action against the background behavioral depression evoked by swimming stress.