Effects of chronic irisin treatment on brain monoamine levels in the hypothalamic and subcortical nuclei of adult male and female rats: An HPLC-ECD study

The role of exercise-related FNDC5/irisin in depression

The complexity of depression presents a significant challenge to traditional treatment methods, such as medication and psychotherapy. Recent studies have shown that exercise can effectively reduce depressive symptoms, offering a new alternative for treating depression. However, some depressed patients are unable to engage in regular physical activity due to age, physical limitations, and other factors. Therefore, pharmacological agents that mimic the effects of exercise become a potential treatment option. A newly discovered myokine, irisin, which is produced during exercise via cleavage of its precursor protein fibronectin type III domain-containing protein 5 (FNDC5), plays a key role in regulating energy metabolism, promoting adipose tissue browning, and improving insulin resistance. Importantly, FNDC5 can promote neural stem cell differentiation, enhance neuroplasticity, and improve mood and cognitive function. This review systematically reviews the mechanisms of action of exercise in the treatment of depression, outlines the physiology of exercise-related irisin, explores possible mechanisms of irisin's antidepressant effects. The aim of this review is to encourage future research and clinical applications of irisin in the prevention and treatment of depression.

Effect of cyclodextrin-complexed lyophilized nanosuspension of Nigella sativa seeds oleoresin on chronic unpredictable mild stress (CUMS)-induced depression in mice

Depression is a prevalent global health concern necessitating alternative approaches to conventional antidepressant medications due to its associated adverse effects. Nigella sativa (NS) is recognized for its potential as an antidepressant, offering a promising solution with fewer side effects. This study investigated the antidepressant efficacy of cyclodextrin-complexed lyophilized nanosuspension of NS oleoresin (NSOR) in a murine model of chronic unpredictable mild stress (CUMS)-induced depression. This study sought to evaluate and contrast the antidepressant potential of the nano-NSOR with that of the NS ethanolic extract (NSEE). The prepared nano-NSOR was characterized physicochemically and evaluated for in vitro drug release and in vivo antidepressant activity. The particle size of nano-NSOR was determined to be 164.6 nm. In vitro drug release studies suggested the higher drug release from nano-NSOR (90.15 % after 72 h) compared to the native NSOR (59.55 % after 72 h). Furthermore, nano-NSOR exhibited a more pronounced antidepressant effect than NSEE in the context of CUMS-induced depression. This study highlights a potential alternative for managing depression, addressing the need for improved antidepressant treatments with reduced side effects. These results suggest that nano-NSOR ameliorates CUMS-induced depression by modulating neurotransmitter levels, reducing inflammation, and enhancing neuroprotection.

Possible role of exercise therapy on depression: Effector neurotransmitters as key players

About 280 million people suffer from depression as the most common neurological disorder and the most common cause of death worldwide. Exercise with serotonin released in the brain by the 5-HT3-IGF-1 mechanism can lead to antidepressant effects. Swimming exercise has antidepressant effects by increasing the sensitivity of serotonin 5-HT2 receptors and postsynaptic 5-HT1A receptors, increasing 5-HT and 5HIAA levels, increasing TPH and serotonin, and decreasing inflammatory levels of IFN-γ and TNF-α. Anaerobic and aerobic exercises increase beta-endorphin, enkephalin, and dynorphin and have antidepressant effects. Exercise by increasing dopamine, D1R, and D2R leads to the expression of BDNF and activation of TrkB and has antidepressant behavior. Exercise leads to a significant increase in GABAAR (γ2 and α2 subunits) and reduces neurodegenerative disorders caused by GABA imbalance through anti-inflammatory pathways. By increasing glutamate and PGC1α and reducing glutamatergic neurotoxicity, exercise enhances neurogenesis and synaptogenesis and prevents neurodegeneration and the onset of depression. Irisin release during exercise shows an important role in depression by increasing dopamine, BDNF, NGF, and IGF-1 and decreasing inflammatory mediators such as IL-6 and IL-1β. In addition, exercise-induced orexin and NPY can increase hippocampal neurogenesis and relieve depression. After exercise, the tryptophan to large neutral amino acids (TRP/LNAA) ratio and the tryptophan to branched-chain amino acids (BCAA) ratio increase, which may have antidepressant effects. The expression of M5 receptor and nAChR α7 increases after exercise and significantly increases dopamine and acetylcholine and ameliorates depression. It appears that during exercise, muscarinic receptors can reduce depression through dopamine in the absence of acetylcholine. Therefore, exercise can be used to reduce depression by affecting neurotransmitters, neuromodulators, cytokines, and/or neurotrophins.

The High-Precision Liquid Chromatography with Electrochemical Detection (HPLC-ECD) for Monoamines Neurotransmitters and Their Metabolites: A Review

This review highlights the advantages of high-precision liquid chromatography with an electrochemical detector (HPLC-ECD) in detecting and quantifying biological samples obtained through intracerebral microdialysis, specifically the serotonergic and dopaminergic systems: Serotonin (5-HT), 5-hydroxyindolacetic acid (5-HIAA), 3,4-dihydroxyphenylacetic acid (DOPAC), dopamine (DA), 3-metoxytryptamin (3-MT) and homovanillic acid (HVA). Recognized for its speed and selectivity, HPLC enables direct analysis of intracerebral microdialysis samples without complex derivatization. Various chromatographic methods, including reverse phase (RP), are explored for neurotransmitters (NTs) and metabolites separation. Electrochemical detector (ECD), particularly with glassy carbon (GC) electrodes, is emphasized for its simplicity and sensitivity, aimed at enhancing reproducibility through optimization strategies such as modified electrode materials. This paper underscores the determination of limits of detection (LOD) and quantification (LOQ) and the linear range (L.R.) showcasing the potential for real-time monitoring of compounds concentrations. A non-exhaustive compilation of literature values for LOD, LOQ, and L.R. from recent publications is included.

Sex-specific effects of neuromodulatory drugs on normal and stress-induced social dominance and aggression in rats

BACKGROUND

Social hierarchies are important for individual's well-being, professional and domestic growth, harmony of the society, as well as survival and morbidity. Studies have revealed sexual dimorphism in the social abilities; however, data is limited on the sex-specific effects of various drugs used to treat psychiatric disorders and social deficits.

OBJECTIVE

The present study aimed at evaluating the sex-dependent effects of Risperidone (antipsychotic that targets D2 dopaminergic, 5HT2A serotonergic, and α-adrenergic receptors), Donepezil (a reversible acetylcholinesterase inhibitor), and Paroxetine (a selective serotonin reuptake inhibitor) on social hierarchy in rats under normal and stressed states.

METHODS

8-12 weeks old male and female Wistar rats were divided into sex-wise 4-4 groups, i.e., 1. control group, 2. Risperidone treated group (3 mg/kg/day), 3. Donepezil treated group (5 mg/kg/day), and Paroxetine treated group (10 mg/kg/day). Rats were treated with these drugs in phase I for 21 days in distilled drinking water, followed by a no (drugs) treatment break of 10 days. After the break phase II started with the administration of drugs (same as in phase I) along with tilt-cage stress for 21 days. Home cage activity assessment was performed once a week during both phases (I & II), while tube dominance and resident intruder tests were performed at the end of each phase.

RESULTS

In phase I in both sexes, Risperidone treatment decreased social interaction and motor activity while Paroxetine treatment increased these in both sexes compared to their respective control groups. Social dominance and aggression were reduced after treatment with both of these drugs. In contrast, Donepezil treatment caused an increase in motor activity in females whereas reduced motor activity in males. Furthermore, Donepezil treatment caused reduction in interaction but increased social dominance and aggression were observed in both sexes. In phase II, stress led to an overall decrease in motor activity and social interaction of animals. Treatment with Risperidone, Paroxetine, and Donepezil caused a sex-specific effect on, motor activity, social interaction, and social exploration.

CONCLUSION

These results showed that Risperidone has stronger effects on male social behavior whereas Paroxetine and Donepezil differentially affect social abilities in both sexes during normal and stressed situations.

Sexually Dimorphic Effects of Neuromodulatory Drugs on Normal and Stress-Induced Social Interaction in Rats

Social behavior is a complex term which involves different interactions between various individuals of a community. It is controlled by different neurotransmitter systems in a sexually dimorphic way. Certain environmental factors, like stress, cause various neurological disorders with associated social abnormalities in a sexually dimorphic way. Multiple drugs are used in clinical settings to treat behavioral disorders. However, the sexually dimorphic effects of these drugs, particularly on social behavior, still need to be studied. The present study was designed to investigate the sex-dependent effects of Risperidone, Donepezil, and Paroxetine in 8-12 weeks old male and female rats under normal and stressed conditions. There were four male and four female groups, i.e., control group (no drug treatment), Risperidone (3 mg/kg/day) treated group, Donepezil (5 mg/kg/day) treated group, and Paroxetine (10 mg/kg/day) treated group. Each group received its respective drug during phase 1 for 21 days, followed by a 10-day break with no drug treatment. After the break, same groups received the same drugs along with tilt-cage stress for an additional 21 days during phase 2. A social preference and novelty test was performed at the end of both phases (1 and 2). During phase 1, Risperidone treatment caused impaired social behavior and reduced locomotion in the male group only, compared to its control group. Donepezil treatment caused a reduction in social interaction, while Paroxetine treatment caused increased social interaction and locomotion in a sex-dependent manner. During phase 2, social novelty was affected in both male and female stress groups. Treatment with drugs along with stress showed differential sex-dependent effects. The study showed a predominant effect of Risperidone on males while there were differential effects of Donepezil and Paroxetine on both sexes. This study has paved the way for the development of more targeted and effective neuromodulatory drugs for use against various psychiatric and social deficits.