Neurobehavioural complications of sleep deprivation: Shedding light on the emerging role of neuroactive steroids

The therapeutic effects of saikosaponins on depression through the modulation of neuroplasticity: From molecular mechanisms to potential clinical applications

Depression is a major global health issue that urgently requires innovative and precise treatment options. In this context, saikosaponin has emerged as a promising candidate, offering a variety of therapeutic benefits that may be effective in combating depression. This review delves into the multifaceted potential of saikosaponins in alleviating depressive symptoms. We summarized the effects of saikosaponins on structural and functional neuroplasticity, elaborated the regulatory mechanism of saikosaponins in modulating key factors that affect neuroplasticity, such as inflammation, the hypothalamic-pituitary-adrenal (HPA) axis, oxidative stress, and the brain-gut axis. Moreover, this paper highlights existing gaps in current researches and outlines directions for future studies. A detailed plan is provided for the future clinical application of saikosaponins, advocating for more targeted researches to speed up its transition from preclinical trials to clinical practice.

Agomelatine efficacy in treatment resistant obsessive-compulsive disorder: A randomized double-blind clinical trial

BACKGROUND

Obsessive-compulsive disorder (OCD) is a prevalent and burdensome mental health condition, often resistant to conventional treatments. Agomelatine (Valdoxan), a compound acting on serotonin and melatonin systems, has shown promise in anecdotal reports and case studies for OCD treatment.

METHODS

A randomized, double-blind clinical trial was conducted with 60 patients diagnosed with treatment-resistant OCD. Participants were divided into an intervention group (receiving agomelatine 50 mg/day) and a control group (placebo). OCD symptoms were assessed using the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) over a 12-week period.

RESULTS

There were no significant differences in age, gender, or baseline Y-BOCS scores between the groups. Agomelatine did not demonstrate a significant improvement in OCD symptoms compared to the placebo. Adverse events were comparable between groups, and liver enzyme levels remained within the normal range.

CONCLUSION

This study, while not confirming significant efficacy, underscores the need for continued investigation into agomelatine's potential in treating specific subgroups of OCD patients, emphasizing the necessity for more comprehensive and well-controlled trials in the future.

Exploring Astrocyte-Mediated Mechanisms in Sleep Disorders and Comorbidity

Astrocytes, the most abundant cells in the brain, are integral to sleep regulation. In the context of a healthy neural environment, these glial cells exert a profound influence on the sleep-wake cycle, modulating both rapid eye movement (REM) and non-REM sleep phases. However, emerging literature underscores perturbations in astrocytic function as potential etiological factors in sleep disorders, either as protopathy or comorbidity. As known, sleep disorders significantly increase the risk of neurodegenerative, cardiovascular, metabolic, or psychiatric diseases. Meanwhile, sleep disorders are commonly screened as comorbidities in various neurodegenerative diseases, epilepsy, and others. Building on existing research that examines the role of astrocytes in sleep disorders, this review aims to elucidate the potential mechanisms by which astrocytes influence sleep regulation and contribute to sleep disorders in the varied settings of brain diseases. The review emphasizes the significance of astrocyte-mediated mechanisms in sleep disorders and their associated comorbidities, highlighting the need for further research.

Gallic Acid Ameliorates Cognitive Impairment Caused by Sleep Deprivation through Antioxidant Effect

Sleep deprivation (SD) has a profound impact on the central nervous system, resulting in an array of mood disorders, including depression and anxiety. Despite this, the dynamic alterations in neuronal activity during sleep deprivation have not been extensively investigated. While some researchers propose that sleep deprivation diminishes neuronal activity, thereby leading to depression. Others argue that short-term sleep deprivation enhances neuronal activity and dendritic spine density, potentially yielding antidepressant effects. In this study, a two-photon microscope was utilized to examine the calcium transients of anterior cingulate cortex (ACC) neurons in awake SD mice in vivo at 24-hour intervals. It was observed that SD reduced the frequency and amplitude of Ca2+ transients while increasing the proportions of inactive neurons. Following the cessation of sleep deprivation, neuronal calcium transients demonstrated a gradual recovery. Moreover, whole-cell patch-clamp recordings revealed a significant decrease in the frequency of spontaneous excitatory post-synaptic current (sEPSC) after SD. The investigation also assessed several oxidative stress parameters, finding that sleep deprivation substantially elevated the level of malondialdehyde (MDA), while simultaneously decreasing the expression of Nuclear Factor erythroid 2-Related Factor 2 (Nrf2) and activities of Superoxide dismutase (SOD) in the ACC. Importantly, the administration of gallic acid (GA) notably mitigated the decline of calcium transients in ACC neurons. GA was also shown to alleviate oxidative stress in the brain and improve cognitive impairment caused by sleep deprivation. These findings indicate that the calcium transients of ACC neurons experience a continuous decline during sleep deprivation, a process that is reversible. GA may serve as a potential candidate agent for the prevention and treatment of cognitive impairment induced by sleep deprivation.

X-linked ichthyosis: New insights into a multi-system disorder

Background

X-linked ichthyosis (XLI) is a rare genetic condition almostexclusively affecting males; it is characterised by abnormal desquamation and retentionhyperkeratosis, and presents with polygonal brown scales. Most cases resultfrom genetic deletions within Xp22.31 spanning the STS (steroid sulfatase)gene, with the remaining cases resulting from STS-specific mutations. For manyyears it has been recognised that individuals with XLI are at increased risk ofcryptorchidism and corneal opacities.

Methods

We discuss emerging evidence that such individuals are alsomore likely to be affected by a range of neurodevelopmental and psychiatrictraits, by cardiac arrhythmias, and by rare fibrotic and bleeding-relatedconditions. We consider candidate mechanisms that may confer elevatedlikelihood of these individual conditions, and propose a novel commonbiological risk pathway.

Results

Understanding the prevalence, nature and co-occurrence ofcomorbidities associated with XLI is critical for ensuring early identificationof symptoms and for providing the most effective genetic counselling andmultidisciplinary care for affected individuals.

Conclusion

Future work in males with XLI, and in new preclinical andcellular model systems, should further clarify underlying pathophysiologicalmechanisms amenable to therapeutic intervention.

A review on pathophysiological aspects of Sleep Deprivation

Sleep deprivation (SD) (also referred as insomnia) is a condition in which peoples fails to get enough sleep due to excessive yawning, facing difficulty to learn new concepts, forgetfulness as well as depressed mood. This could be occurs due to several possible reasons including medications, stress (caused by shift work). Despite the fact that sleep is important for the normal physiology, it currently affects millions of people around the world US (70 million) and Europe (45 million). Due to increase work demand nowadays lots of peoples experiencing sleep deprivation hence, this could be the reason for several car accident followed by death and morbidity. This review highlighted the impact of SD on neurotransmitter release and functions, theories (Flip-flop theory, oxidative stress theory, neuroinflammation theory, neurotransmitter theory, and hormonal theory) associated with SD pathogenesis apart from this it also demonstrate the molecular pathways underlying SD (PI3K and Akt , NF-κB, Nrf2, and adenosine pathway. However, this study also elaborates the SD induced changes in the level of neurotransmitters, hormonal, and mitochondrial functions. Along with this, it also covers several molecular aspects associated with SD as well. Through this study a link is made between SD and associated causes, which will further help to develop potential therapeutic strategy against SD.

Allopregnanolone and depression and anxiety symptoms across the peripartum: an exploratory study

Recent research has implicated allopregnanolone (ALLO), a neuroactive steroid and metabolite of progesterone, in perinatal mood and anxiety symptoms. We sought to add to the limited literature examining ALLO and mood and anxiety at multiple time points across the peripartum. We measured mood and anxiety symptoms and ALLO levels by ELISA at the second and third trimester (T2 and T3) and week 6 postpartum (W6) in N = 73 women with prior histories of mood and/or anxiety disorders and N = 38 healthy controls. Analytic methods included multivariate and logistic regressions with linear mixed effect models. Among all participants (N = 111), higher ALLO levels at W6 were associated with higher depression and anxiety scores: each one unit increase in log ALLO at W6 was associated with a 2.54 point increase on the Edinburgh Postnatal Depression Scale (EPDS) (95% CI: 0.73 to 4.33) and an 8.0 point increase on the Perinatal Anxiety Screening Scale (PASS) (95% CI: 3.82 to 12.6). In addition, the nature of the relationship between log ALLO level and psychological measures changed across time; from T2 to W6 for EPDS, β = 3.73 (95% CI:1.16, 6.30), p = 0.0045; for PASS β = 9.78 (95% CI:3.77, 15.79), p = 0.0014); from T3 to W6, for (EPDS, β = 2.52 (95% CI:0.08, 4.96), p = 0.043; for PASS β = 7.33 (95% CI:1.63, 13.02), p = 0.018). The relationship of log ALLO to mood and anxiety symptoms was the same among women with and without psychiatric histories. Our exploratory findings indicate that the relationship between ALLO and mood and anxiety symptoms may change across the peripartum.

Preoptic Area Modulation of Arousal in Natural and Drug Induced Unconscious States

The role of the hypothalamic preoptic area (POA) in arousal state regulation has been studied since Constantin von Economo first recognized its importance in the early twentieth century. Over the intervening decades, the POA has been shown to modulate arousal in both natural (sleep and wake) as well as drug-induced (anesthetic-induced unconsciousness) states. While the POA is well known for its role in sleep promotion, populations of wake-promoting neurons within the region have also been identified. However, the complexity and molecular heterogeneity of the POA has made distinguishing these two populations difficult. Though multiple lines of evidence demonstrate that general anesthetics modulate the activity of the POA, the region's heterogeneity has also made it challenging to determine whether the same neurons involved in sleep/wake regulation also modulate arousal in response to general anesthetics. While a number of studies show that sleep-promoting POA neurons are activated by various anesthetics, recent work suggests this is not universal to all arousal-regulating POA neurons. Technical innovations are making it increasingly possible to classify and distinguish the molecular identities of neurons involved in sleep/wake regulation as well as anesthetic-induced unconsciousness. Here, we review the current understanding of the POA's role in arousal state regulation of both natural and drug-induced forms of unconsciousness, including its molecular organization and connectivity to other known sleep and wake promoting regions. Further insights into the molecular identities and connectivity of arousal-regulating POA neurons will be critical in fully understanding how this complex region regulates arousal states.

Allopregnanolone Decreases Evoked Dopamine Release Differently in Rats by Sex and Estrous Stage

Mesolimbic dopamine transmission is dysregulated in multiple psychiatric disorders, including addiction. Previous studies found that the endogenous GABAergic steroid (3α,5α)-3-hydroxy-5-pregnan-20-one (allopregnanolone) modulates dopamine levels in the nucleus accumbens and prefrontal cortex. As allopregnanolone is a potent positive allosteric modulator of GABA_A receptors, and GABA_A receptors can regulate dopamine release, we hypothesized that allopregnanolone would reduce phasic fluctuations in mesolimbic dopamine release that are important in learning and reward processing. We used fast-scan cyclic voltammetry in anesthetized female and male rats to measure dopamine release in the nucleus accumbens evoked by electrical stimulation of the ventral tegmental area, before and after administration of allopregnanolone. Allopregnanolone (7.5–25 mg/kg, IP) reduced evoked dopamine release in both male and female rats, compared to β-cyclodextrin vehicle. In males, all doses of allopregnanolone decreased dopamine transmission, with stronger effects at 15 and 25 mg/kg allopregnanolone. In females, 15 and 25 mg/kg allopregnanolone reduced dopamine release, while 7.5 mg/kg allopregnanolone was no different from vehicle. Since allopregnanolone is derived from progesterone, we hypothesized that high endogenous progesterone levels would result in lower sensitivity to allopregnanolone. Consistent with this, females in proestrus (high progesterone levels) were less responsive to allopregnanolone than females in other estrous cycle stages. Furthermore, 30 mg/kg progesterone reduced evoked dopamine release in males, similar to allopregnanolone. Our findings confirm that allopregnanolone reduces evoked dopamine release in both male and female rats. Moreover, sex and the estrous cycle modulated this effect of allopregnanolone. These results extend our knowledge about the pharmacological effects of neurosteroids on dopamine transmission, which may contribute to their therapeutic effects.

Resilience to acute sleep deprivation is associated with attenuation of hippocampal mediated learning impairment

BACKGROUND

Sleep deprivation is a universal issue that affects individuals in different ways. While some individuals experience a deficit in performance, others experience resiliency as they maintain high levels of physical and mental activity. Sleep loss is known to cause cognitive dysfunction in areas such as learning and memory, but little is known about neural mechanisms that contribute to resilience to this adverse effect.

METHODS

An existing database of a learning paradigm in sleep deprived and non-sleep deprived 16 to 18-month old C57BL/6 mice was used to identify fast learners and slow learners based on an R2 value representing the learning curve of each individual mouse.

RESULTS

Results showed that sleep deprived mice had more slow learners compared to fast learners whereas non-sleep-deprived mice showed the opposite. Hippocampal immunohistochemistry and digital imaging analysis showed sleep deprived, fast learners expressed lower levels of monocyte chemoattractant protein-1 and histone deacetylase 2 and higher levels of synaptophysin and brain-derived neurotrophic factor compared to sleep-deprived slow learners.

CONCLUSIONS

These observations provide evidence to suggest that sleep-deprived mice that performed well in a cognitive assay show less hippocampal mediated learning impairment and provide the rationale for further investigations into neurobiological resilience to sleep deprivation with increasing age.