Two combined amino acids promote sleep activity in caffeine-induced sleepless model systems

Sleep apnoea, gut dysbiosis and cognitive dysfunction

Sleep disorders are becoming increasingly common, and their distinct effects on physical and mental health require elaborate investigation. Gut dysbiosis (GD) has been reported in sleep-related disorders, but sleep apnoea is of particular significance because of its higher prevalence and chronicity. Cumulative evidence has suggested a link between sleep apnoea and GD. This review highlights the gut-brain communication axis that is mediated via commensal microbes and various microbiota-derived metabolites (e.g. short-chain fatty acids, lipopolysaccharide and trimethyl amine N-oxide), neurotransmitters (e.g. γ-aminobutyric acid, serotonin, glutamate and dopamine), immune cells and inflammatory mediators, as well as the vagus nerve and hypothalamic-pituitary-adrenal axis. This review also discusses the pathological role underpinning GD and altered gut bacterial populations in sleep apnoea and its related comorbid conditions, particularly cognitive dysfunction. In addition, the review examines the preclinical and clinical evidence, which suggests that prebiotics and probiotics may potentially be beneficial in sleep apnoea and its comorbidities through restoration of eubiosis or gut microbial homeostasis that regulates neural, metabolic and immune responses, as well as physiological barrier integrity via the gut-brain axis.

Network Pharmacology Analysis of the Potential Pharmacological Mechanism of a Sleep Cocktail

Insomnia, also known as sleeplessness, is a sleep disorder due to which people have trouble sleeping, followed by daytime sleepiness, low energy, irritability, and a depressed mood. It may result in an increased risk of accidents of all kinds as well as problems focusing and learning. Dietary supplements have become popular products for alleviating insomnia, while the lenient requirements for pre-market research result in unintelligible mechanisms of different combinations of dietary supplements. In this study, we aim to systematically identify the molecular mechanisms of a sleep cocktail's pharmacological effects based on findings from network pharmacology and molecular docking. A total of 249 targets of the sleep cocktail for the treatment of insomnia were identified and enrichment analysis revealed multiple pathways involved in the nervous system and inflammation. Protein-protein interaction (PPI) network analysis and molecular complex detection (MCODE) analysis yielded 10 hub genes, including AKT1, ADORA1, BCL2, CREB1, IL6, JUN, RELA, STAT3, TNF, and TP53. Results from weighted correlation network analysis (WGCNA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of insomnia-related transcriptome data from peripheral blood mononuclear cells (PBMCs) showed that a sleep cocktail may also ease insomnia via regulating the inflammatory response. Molecular docking results reveal good affinity of Sleep Cocktail to 9 selected key targets. It is noteworthy that the crucial target HSP90AA1 binds to melatonin most stably, which was further validated by MD simulation.

Effects of Dendropanax morbiferus Leaf Extract on Sleep Parameters in Invertebrate and Vertebrate Models

Dendropanax morbiferus is highly valued in traditional medicine and has been used to alleviate the symptoms of numerous diseases owing to its excellent antioxidant activity. This study aimed to evaluate the sleep promotion and related signaling pathways of D. morbiferus extract (DE) via behavioral analysis, molecular biological techniques, and electrophysiological measurements in invertebrate and vertebrate models. In Drosophila, the group treated with 4% DE experienced decreased subjective nighttime movement and sleep bout and increased total sleeping time. Moreover, substantial changes in locomotor activity, including distance moved, velocity, and movement, were confirmed in the 4% DE-treated group. Compared to Drosophila in which insomnia and oxidative stress were induced by exposure to 0.1% caffeine, the DE-treated group improved sleep-related parameters to the level of the normal group. In the Drosophila model, exposure to 4% DE upregulated the expression of gamma-aminobutyric acid (GABA)-related receptors and serotonin receptor (5-HT1A), along with the expression of antioxidant-related factors, glutathione, and catalase. In the pentobarbital-induced sleep test using ICR mice, the duration of sleep was markedly increased by high concentration of DE. In addition, through the electroencephalography analysis of SD-rats, a significant increase in non-rapid-eye-movement sleep and delta waves was confirmed with high concentrations of DE administration. The increase in sleep time and improvement in sleep quality were confirmed to be related to the expression of altered GABA receptors and the enhancement of the contents of the neurotransmitters GABA and serotonin (5-HT) because of high DE administration. High-dose administration of DE also increased the expression of antioxidant-related factors in the brain and significantly decreased malondialdehyde content. Taken together, DE induced improvements in sleep quantity and quality by regulating neurotransmitter content and related receptor expression, along with high antioxidant activity, and may have a therapeutic effect on sleep disorders.

Prolonging effects of Valeriana fauriei root extract on pentobarbital-induced sleep in caffeine-induced insomnia model mice and the pharmacokinetics of its active ingredients under conditions of glycerol fatty acid ester as emulsifiers

ETHNOPHARMACOLOGICAL RELEVANCE

Valeriana plant roots have traditionally been used to treat central nervous system-related disorders in European countries. Among this genus, the Japanese Pharmacopoeia registers the dried roots of V. fauriei Briq. (VF). However, insufficient pharmacological data are available for this species.

AIM OF THE STUDY

We investigated the sedative effects of VF extract in a murine caffeine-induced insomnia model as well as the active ingredients and their pharmacokinetics to determine its basic pharmacological action mechanisms under conditions glycerol fatty acid ester is used as emulsifiers.

MATERIALS AND METHODS

A murine insomnia model was created by caffeine. Samples derived from the ethanol extract of VF were administered per oral (p.o.), and caffeine was injected intraperitoneally (i.p.). Pentobarbital was injected i.p. and the sleep latency and duration were measured. To confirm the mechanism of action of VF, flumazenil, a specific γ-aminobutyric acid receptor type A (GABA_A receptor) antagonist, was administered (i.p.) immediately prior to the sample administration. We examined the pharmacokinetic profiles of the active ingredients in the plasma, brain, urine, and feces of mice after the administration (p.o and intravenous (i.v.)) of VF samples.

RESULTS

VF extract (5 g as VF/kg, p.o.) significantly shorten sleep latency and prolonged pentobarbital-induced sleep in caffeine-induced insomnia mice, partially mediated via the GABAergic nervous system, although a higher dose (10 g as VF/kg, p.o.) was required to exhibit the significant effects in normal mice. Kessyl glycol diacetate (KGD), the main constitutive compound in VF, did not shorten sleep latency but exhibited the same sleep prolonged effect at a dose related to VF extract. The concentration of kessyl glycol 8-acetate (KG8) in the plasma was higher than that of KGD in mice treated (p.o.) with VF extract. The profiles of brain concentrations of KGD and KG8 were similar to those in the plasma, and approximately 20% of those in the plasma were distributed throughout the brain. The excretions of KGD and KG8 in urine and feces was slightly detected, and an unknown large peak related to KG8 was detected in the urine of mice administered with VF extract by HPLC-MS/MS analysis.

CONCLUSIONS

VF exhibits more sedative effects under stressed conditions, such as insomnia, and the major active ingredients are KGD and its metabolite KG8, which are distributed from the blood circulation into the brain by simple diffusion. KG8 is further metabolized into other metabolites that are easily excreted in the urine.

Characterization of sleep-related neurochemicals in the different developmental stages and insomnia models of Drosophila melanogaster

Neurotransmitters play an important role in regulating the physiological activity of the animal, especially in emotion and sleep. While nucleotides are involved in almost all cellular processes. However, the characteristics of sleep-related neurochemicals under different life cycles and environment remain poorly understood. A rapid and sensitive analytical method was established with LC-MS/MS to determine eight endogenous neurochemicals in Drosophila melanogaster and the levels of neurochemicals in the different developmental stages of Drosophila melanogaster were evaluated. The results indicated that there were significant discrepancies among different stages, especially from pupal stage to adult. The levels of these compounds in caffeine-induced insomnia model of Drosophila melanogaster were investigated. Compared with normal group the eight endogenous metabolites did not fluctuate significantly in insomnia Drosophila melanogaster, which may be due to the mechanism of caffeine-induced insomnia through other pathways, such as adenosine. The results provide a reference for decoding of neurochemicals involved in the development of the full cycle of mammalian life and exploration of insomnia even other mental diseases induced by exogenous substances in the future.

Changes in Locomotor Activity and Oxidative Stress-Related Factors after the Administration of an Amino Acid Mixture by Generation and Age

Amino acids, as nutrients, are expected to improve sleep disorders. This study aimed to evaluate the generation- and age-dependent sleep-improving effects of γ-aminobutyric acid (GABA) and 5-hydroxytryptophan (5-HTP) coadministration. The differentially expressed genes and generation-related behavior after the administration of a GABA/5-HTP mixture were measured in a Drosophila model, while age-related changes in gene expression and oxidative stress-related parameters were measured in a mouse model. The GABA/5-HTP-treated group showed significant behavioral changes compared to the other groups. Sequencing revealed that the GABA/5-HTP mixture influenced changes in nervous system-related genes, including those involved in the regulation of the expression of behavioral and synaptic genes. Additionally, total sleep time increased with age, and nighttime sleep time in the first- and third-generation flies was significantly different from that of the control groups. The GABA/5-HTP mixture induced significant changes in the expression of sleep-related receptors in both models. Furthermore, the GABA/5-HTP mixture reduced levels of ROS and ROS reaction products in an age-dependent manner. Therefore, the increase in behavioral changes caused by GABA/5-HTP mixture administration was effective in eliminating ROS activity across generations and ages.

Integrated Screening of Effective Anti-Insomnia Fractions of Zhi-Zi-Hou-Po Decoction via Drosophila melanogaster and Network Pharmacology Analysis of the Underlying Pharmacodynamic Material and Mechanism

Insomnia is an anabatic epidemiology, while the mechanism is extremely complicated; it remains one of the major scientific challenges in life sciences. Because of the advantage of having a similar genetic background and circadian rhythm as those of humans, the Drosophila melanogaster model organism is hugely popular in sleep-related drug screening studies. Seven-day-old virgin D. melanogaster was used to establish the sleep deprivation model by repeated light stimulation at night. Using PySolo activity monitoring system and Drosophila activity as indices, the effective fractions of Zhi-Zi-Hou-Po decoction (ZZHPD) for insomnia were screened; the content of monoamine neurotransmitters dopamine (DA), 5-hydroxyindole-3-acetic acid (5-HIAA), Homovanillic acid (HVA), and 5-hydroxytryptamine (5-HT) in the brain of D. melanogaster were determined by high-performance liquid chromatography-electro-chemical detection. The herb-compound-target-disease target network were further constructed through network pharmacology to identify the potential targets and pathways of ZZHPD in the intervention of insomnia. Finally, the molecular docking method was used for evaluating the binding characteristics of important compounds from ZZHPD with related targets. The results showed that a certain dose of ZZHPD and its petroleum ether, dichloromethane, ethyl acetate, and n-butanol fractions could improve sleep. The dichloromethane fraction from ZZHPD extracts showed the best anti-insomnia effect among all extracts. It can also reduce the content of DA and HVA in the brain of D. melanogaster and increase 5-HT and 5-HIAA levels. The network pharmacology showed that the main active ingredients in ZZHPD included magnolol, honokiol, hesperidin, and so forth. According to the screening conditions, there were 71 targets and the result of KEGG enrichment analysis revealed that 73 pathways were associated with insomnia, which were primarily involved in inflammatory response, central neurotransmitter regulation, and apoptosis to relieve insomnia. The molecular docking results clarified that naringenin and apigenin have an intimate relationship with GABA_A receptor, histamine H1, orexin receptor type 2, and interleukin-6. The mechanism of relieving insomnia is the result of the interaction of multi-components, multi-targets, and multi-pathways, which provides a certain theoretical basis for the treatment of insomnia and related diseases as well as clinical research.

Smoking flies: testing the effect of tobacco cigarettes on heart function of Drosophila melanogaster

Studies about the relationship between substances consumed by humans and their impact on health, in animal models, have been a challenge due to differences between species in the animal kingdom. However, the homology of certain genes has allowed extrapolation of certain knowledge obtained in animals. Drosophila melanogaster, studied for decades, has been widely used as model for human diseases as well as to study responses associated with the consumption of several substances. In the present work we explore the impact of tobacco consumption on a model of 'smoking flies'. Throughout these experiments, we aim to provide information about the effects of tobacco consumption on cardiac physiology. We assessed intracellular calcium handling, a phenomenon underlying cardiac contraction and relaxation. Flies chronically exposed to tobacco smoke exhibited an increased heart rate and alterations in the dynamics of the transient increase of intracellular calcium in myocardial cells. These effects were also evident under acute exposure to nicotine of the heart, in a semi-intact preparation. Moreover, the alpha 1 and 7 subunits of the nicotinic receptors are involved in the heart response to tobacco and nicotine under chronic (in the intact fly) as well as acute exposure (in the semi-intact preparation). The present data elucidate the implication of the intracellular cardiac pathways affected by nicotine on the heart tissue. Based on the probed genetic and physiological similarity between the fly and human heart, cardiac effects exerted by tobacco smoke in Drosophila advances our understanding of the impact of it in the human heart. Additionally, it may also provide information on how nicotine-like substances, e.g. neonicotinoids used as insecticides, affect cardiac function.This article has an associated First Person interview with the first author of the paper.

Hypnotic Effects of Lactobacillus fermentum PS150TM on Pentobarbital-Induced Sleep in Mice

The bidirectional communication between the gastrointestinal tract and the central nervous system appears to be functionally linked to the intestinal microbiome, namely the microbiome-gut-brain axis (MGBA). Probiotics with health benefits on psychiatric or neurological illnesses are generally called psychobiotics, and some of them may also be able to improve sleep by targeting the MGBA. This study aimed to investigate the effects of a psychobiotic strain, Lactobacillus fermentum PS150TM (PS150TM), on sleep improvement by using a pentobarbital-induced sleep mouse model. Compared with the vehicle control group, the oral administration of PS150TM, but not the other L. fermentum strains, significantly decreased the sleep latency and increased the sleep duration of mice, suggesting strain-specific sleep-improving effects of PS150TM. Moreover, the ingestion of diphenhydramine, an antihistamine used to treat insomnia, as a drug control group, only increased the sleep duration of mice. We also found that the sleep-improving effects of PS150TM are time- and dose-dependent. Furthermore, the oral administration of PS150TM could attenuate a caffeine-induced sleep disturbance in mice, and PS150TM appeared to increase the expression of the gene encoding the adenosine 1 receptor in the hypothalamus of mice, as assessed by quantitative real-time polymerase chain reaction. Taken together, our results present a potential application of PS150TM as a dietary supplement for sleep improvement.