Influence of work shift on glutamic acid and gamma-aminobutyric acid (GABA): evaluation with proton magnetic resonance spectroscopy at 3T

The association between shift work, shift work sleep disorders and premature ejaculation in male workers

OBJECTIVE

Shift work and Shift Work Sleep Disorder (SWSD) are known to affect the secretion of several neurotransmitters and hormones associated with premature ejaculation (PE). However, their specific influence on the regulation of male ejaculation remains unclear. This study explores the relationship between shift work, SWSD, and PE.

METHODS

From April to October 2023, a cross-sectional survey was conducted across five regions of China to explore the work schedules, sleep quality, and sexual function of male workers. Participants' sleep quality was evaluated using a validated SWSD questionnaire, and their erectile function and ejaculatory control were assessed with the International Inventory of Erectile Function (IIEF-5) scores and Premature Ejaculation Diagnostic Tool (PEDT) scores, respectively. Univariate and multivariate linear regression analyses were employed to identify risk factors associated with PE. Confounders were controlled using multiple regression models, and clinical prediction models were developed to predict PE onset and assess the contribution of risk factors.

RESULTS

The study included 1239 eligible participants, comprising 840 non-shift workers and 399 shift workers (148 with SWSD and 251 without SWSD). Compared to non-shift working males, those involved in shift work (β 1.58, 95% CI 0.75 - 2.42, p < 0.001) and those suffering from SWSD (β 2.86, 95% CI 1.86 - 3.85, p < 0.001) they had significantly higher PEDT scores. Additionally, we identified daily sleep of less than six hours, depression, anxiety, diabetes, hyperlipidemia, frequent alcohol consumption (more than twice a week), and erectile dysfunction as risk factors for PE. The predictive model for PE demonstrated commendable efficacy.

CONCLUSION

Both shift work and SWSD significantly increase the risk of premature ejaculation, with the risk magnifying in tandem with the duration of shift work. This study reveals the potential impact of shift work and SWSD on PE and provides new theoretical foundations for the risk assessment and prevention of this condition.

GABAA Receptor-Mediated Sleep-Promoting Effect of Saaz-Saphir Hops Mixture Containing Xanthohumol and Humulone

Hops contain flavonoids that have sedative and sleep-promoting activities such as α-acid, β-acid, and xanthohumol. In this study, the sleep-enhancing activity of a Saaz–Saphir hops mixture was measured. In the caffeine-induced insomnia model, the administration of a Saaz–Saphir mixture increased the sleep time compared to Saaz or Saphir administration alone, which was attributed to the increase in NREM sleep time by the δ-wave increase. Oral administration of the Saaz–Saphir mixture for 3 weeks increased the γ-amino butyric acid (GABA) content in the brain and increased the expression of the GABA_A receptor. As the GABA antagonists picrotoxin and bicuculline showed a decrease in sleep activity, it was confirmed that the GABA_A receptor was involved in the Saaz–Saphir mixture activity. In addition, the GABA_A receptor antagonist also reduced the sleep activity induced by xanthohumol and humulone contained in the Saaz–Saphir mixture. Therefore, xanthohumol and humulone contained in the Saaz–Saphir mixture showed sleep-promoting activity mediated by the GABA_A receptors. The mixture of the Saaz and Saphir hop varieties may thus help mitigate sleep disturbances compared to other hop varieties.

Deletion of FGF9 in GABAergic neurons causes epilepsy

Fibroblast growth factor 9 (FGF9) has long been assumed to modulate multiple biological processes, yet very little is known about the impact of FGF9 on neurodevelopment. Herein, we found that loss of Fgf9 in olig1 progenitor cells induced epilepsy in mice, with pathological changes in the cortex. Then depleting Fgf9 in different neural populations revealed that epilepsy was associated with GABAergic neurons. Fgf9 CKO in GABAergic neuron (CKOVGAT) mice exhibited not only the most severe seizures, but also the most severe growth retardation and highest mortality. Fgf9 deletion in CKOVGAT mice caused neuronal apoptosis and decreased GABA expression, leading to a GABA/Glu imbalance and epilepsy. The adenylate cyclase/cyclic AMP and ERK signaling pathways were activated in this process. Recombinant FGF9 proteoliposomes could significantly decrease the number of seizures. Furthermore, the decrease of FGF9 was commonly observed in serum of epileptic patients, especially those with focal seizures. Thus, FGF9 plays essential roles in GABAergic neuron survival and epilepsy pathology, which could serve as a new target for the treatment of epilepsy.

The fMRI study for acupuncture on shift work sleep disorder: Study protocol for a randomized controlled neuroimaging trial

INTRODUCTION

Nearly 20% of night shift nurses will cause shift work disorder (SWD) due to the disruption of sleep-wake cycle, which not only affects the daily work efficiency, but also brings a huge burden on physical and mental health. Acupuncture is a safe and effective intervention on SWD. This trial will combine with functional magnetic resonance imaging (fMRI) to study the clinical effects and potential mechanism of acupuncture in the treatment of SWD.

METHODS AND ANALYSIS

This is a randomized controlled neuroimaging trial, with enrolled participants, outcome assessors, and data statisticians blinded. 60 patients with SWD and 30 healthy controls who sleep regularly will be recruited and divided into divided into a control group, a true acupoints treatment group (TATG) and a sham acupoints treatment group (SATG) by the ratio of 1:1:1. The TATG and SATG will receive 8 sessions of acupuncture treatment in 4 weeks. Cognitive function scales and MRI scanning will be performed before and after 4-week acupuncture treatment. The control group will receive no intervention. Functional connectivity of intra-network and inter-network will be the primary outcome and effect indicator. The secondary outcomes included Repeatable Battery for the Assessment of Neuropsychological Status, Attentional Network Test, Pittsburgh Sleep Quality Index scale and needle sensation assessment scale. Neuroimage indicators will be correlated with clinical data and scores of cognitive function assessment to explore the possible mechanisms underlying the changes of brain activity caused by acupuncture treatment.

DISCUSSION

The results of this study will enable us to verify the therapeutic effect of acupuncture on SWD and explore the potential central mechanism of acupuncture on SWD from the change of brain activity.

Jiao-tai-wan for insomnia symptoms caused by the disharmony of the heart and kidney: a study protocol for a randomized, double-blind, placebo-controlled trial

BACKGROUND

Insomnia seriously affects people's normal lives and work. However, effective treatment strategies are scarce. The purpose of this study is to explore the efficacy and safety of Jiao-tai-wan (JTW) for ameliorating insomnia symptoms caused by disharmony of the heart and kidney.

DESIGN

This is a randomized, double-blind, placebo-controlled pilot clinical trial. A total of 124 participants suffering from insomnia symptoms will be randomly assigned to the JTW or placebo group in an equal ratio. The participants will be asked to take JTW or placebo granules twice a day for 1 week. All data will be gathered at baseline and at the end of the drug intervention. The primary outcome measures will be the mean change in the Pittsburgh Sleep Quality Index (PSQI) from baseline to the end of the drug intervention. Secondary outcome measures will include the altered sleep parameters in polysomnography, ¹H-magnetic resonance spectroscopy (¹H-MRS) evaluation, the Disharmony of Heart and Kidney Scoring System score, and blood tests, including the levels of serum adenosine and melatonin. A laboratory test will be taken before and after treatment to assess the safety of JTW.

DISCUSSION

The outcomes of this study will confirm the efficacy of JTW for the treatment of insomnia symptoms and will also be used to monitor the safety of JTW.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1800019239. Registered on 1st November 2018.

Fully automated macromolecule suppressed single voxel glutamate spectroscopy (FAMOUS SVGS)

PURPOSE

The aim of the study was to develop and validate a new localized (1)H MRS pulse sequence and automated post-processing software for the quantification of brain Glutamate (Glu) in clinical conditions at 7.0T in order to get reliable and reproducible results for acute intervention studies.

METHODS

Here we describe a new localized proton MRS method "Fully Automated MacrOmolecUle Suppressed Single Voxel Glutamate Spectroscopy (FAMOUS SVGS)" for measuring Glu. FAMOUS SVGS method consists of a new pulse sequence with optimized switchable water, metabolites and outer volume suppression modules, as well as a frequency selective inversion pulse and automated post-processing of the five spectra obtained. FAMOUS SVGS method was first validated with glutamate phantoms and then validated with test-retest repeatability studies in the occipital cortex of five normal volunteers at 7.0T.

RESULTS

Glutamate concentrations estimated from phantoms with FAMOUS SVGS method correlated well with actual concentrations. Test-retest repeatability studies in human brain in vivo yielded less than 0.3 mM intra-subject variations in Glu concentrations.

CONCLUSIONS

FAMOUS SVGS method enables Glu quantification in vivo at 7.0T with test-retest variability of less than 0.3 mM. We expect that we can reliably measure ≥0.5 mM change in glutamate due to any acute intervention.

Neurochemical Changes Associated with Stress-Induced Sleep Disturbance in Rats: In Vivo and In Vitro Measurements

The goal of this study was to quantitatively assess the changes in the cerebral neurochemical profile and to identify those factors that contribute to the alteration of endogenous biomolecules when rats are subjected to stress-induced sleep disturbance. We exposed Sprague-Dawley rats (controls: n = 9; stress-induced sleep perturbation rats: n = 11) to a psychological stressor (cage exchange method) to achieve stress-induced sleep perturbation. In vivo magnetic resonance imaging assessments were carried out using a high-resolution 9.4 T system. For in vivo neurochemical analysis, a single voxel was localized in the right dorsal hippocampal region, and in vivo spectra were quantified for 17 cerebral neurochemical signals. Rats were sacrificed upon completion of the magnetic resonance spectroscopy protocol, and whole-brain tissue was harvested from twenty subjects. The dopamine and serotonin signals were obtained by performing in vitro liquid chromatography-tandem mass spectrometry on the harvested tissue. In the right dorsal hippocampal region, the gamma-aminobutyric-acid (GABA) and glutamine (Gln) concentrations were significantly higher in the sleep-perturbed rats than in the sham controls. The ratios of Gln/Glu (glutamate), Gln/tCr (total-creatine), and GABA/Glu were also significantly higher in the sleep-perturbed group, while serotonin concentrations were significantly lower in the sleep-perturbed rats. Pearson correlation results among individual rat data indicate that concentrations of dopamine (DA) and serotonin (5-HT) were significantly higher in SSP rats. A larger correlation coefficient was also observed for the SSP rats. Analysis of the correlation between the in vivo and in vitro signals indicated that the concentrations of Gln, 5-HT, and DA exhibited a significant negative correlation in the SSP rat data but not in that of control rats. The authors propose that the altered and correlated GABA, Gln, 5-HT, and DA concentrations/ratios could be considered key markers of neurological function in animal models of stress-induced sleep perturbation.

Alterations of GABA and glutamate-glutamine levels in premenstrual dysphoric disorder: a 3T proton magnetic resonance spectroscopy study

Increasing evidence has suggested that the GABAergic neurotransmitter system is involved in the pathogenesis of premenstrual dysphoric disorder (PMDD). We used proton magnetic resonance spectroscopy ((1)H MRS) to investigate whether PMDD is associated with alterations in brain GABA levels. Levels of glutamate-glutamine (Glx) were also explored. Participants comprised 22 women with PMDD and 22 age-matched healthy controls who underwent 3T (1)H MRS during the late luteal phase of the menstrual cycle. GABA+ and Glx levels were quantified in the anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC) and the left basal ganglia (ltBG). Water-scaled GABA+ concentrations and GABA+/tCr ratios were significantly lower in both the ACC/mPFC and ltBG regions of PMDD women than in healthy controls. Glx/tCr ratios were significantly higher in the ACC/mPFC region of PMDD women than healthy controls. Our preliminary findings provide the first report of abnormal levels of GABA+ and Glx in mood-related brain regions of women with PMDD, indicating that dysregulation of the amino acid neurotransmitter system may be an important neurobiological mechanism in the pathogenesis of PMDD.

GABAergic contributions to alcohol responsivity during adolescence: insights from preclinical and clinical studies

There is a considerable body of literature demonstrating that adolescence is a unique age period, which includes rapid and dramatic maturation of behavioral, cognitive, hormonal and neurobiological systems. Most notably, adolescence is also a period of unique responsiveness to alcohol effects, with both hyposensitivity and hypersensitivity observed to the various effects of alcohol. Multiple neurotransmitter systems are undergoing fine-tuning during this critical period of brain development, including those that contribute to the rewarding effects of drugs of abuse. The role of developmental maturation of the γ-amino-butyric acid (GABA) system, however, has received less attention in contributing to age-specific alcohol sensitivities. This review integrates GABA findings from human magnetic resonance spectroscopy studies as they may translate to understanding adolescent-specific responsiveness to alcohol effects. Better understanding of the vulnerability of the GABA system both during adolescent development, and in psychiatric conditions that include alcohol dependence, could point to a putative mechanism, boosting brain GABA, that may have increased effectiveness for treating alcohol use disorders.

Decreased GABA levels in anterior cingulate cortex/medial prefrontal cortex in panic disorder

Changes of various brain metabolites including γ-aminobutyric acid (GABA), measured by 1H-magnetic resonance spectroscopy (MRS), have been reported in panic disorder (PD). Deficits in GABA have been implicated in the pathophysiology of PD. Furthermore, it has been suggested that cortical metabolite changes in PD are familial. Eleven PD patients, including five with and six without a PD family history, and eight age- and gender-matched healthy controls without a family history of psychopathology were recruited. Each subject underwent MRS exams and behavioral assessments (resting visual analog anxiety level and the Panic Disorder Severity Scale). GABA was detected with a MEGA-PRESS J-editing sequence and fitted to minimize macromolecule contaminations. A significant decrease in GABA, expressed as the ratio of GABA over total creatine (GABA/tCr), was detected in the anterior cingulate cortex (ACC)/medial prefrontal cortex (mPFC) in PD patients (p<0.05), which tends to be pronounced in patients with a PD family history. No other patient/control differences in metabolites were noted in the ACC/mPFC or occipital cortex (OCC). Overall, our results indicate that deficits in GABA levels in PD patients vary by brain regions and possibly by family history status.

Overview of potential procedural and participant-related confounds for neuroimaging of the resting state

Studies of intrinsic brain activity in the resting state have become increasingly common. A productive discussion of what analysis methods are appropriate, of the importance of physiologic correction and of the potential interpretations of results has been ongoing. However, less attention has been paid to factors other than physiologic noise that may confound resting-state experiments. These range from straightforward factors, such as ensuring that participants are all instructed in the same manner, to more obscure participant-related factors, such as body weight. We provide an overview of such potentially confounding factors, along with some suggested approaches for minimizing their impact. A particular theme that emerges from the overview is the range of systematic differences between types of study groups (e.g., between patients and controls) that may influence resting-state study results.

GABA-based evaluation of neurologic conditions: MR spectroscopy

SUMMARY

GABA serves as a major neurotransmitter of the brain and functions mainly to inhibit neural excitatory activity. Disruption of the GABAergic processes appears to occur in various neurologic and psychiatric conditions, including epilepsy, mood disorders, motor disorders such as focal dystonia and stiff-person syndrome, sleep disorders, neuroplasticity, and drug and alcohol dependence. These concentration differences may be ascertained by using MR spectroscopy to provide information on the concentration of different metabolites. This review briefly discusses advances in MR spectroscopy methods and explores the application of this technique to detect changes in GABA due to disease processes and medication-induced effects.

Reduced γ-aminobutyric acid in occipital and anterior cingulate cortices in primary insomnia: a link to major depressive disorder?

Insomnia is closely related to major depressive disorder (MDD) both cross-sectionally and longitudinally, and as such, offers potential opportunities to refine our understanding of the neurobiology of both sleep and mood disorders. Clinical and basic science data suggest a role for reduced γ-aminobutyric acid (GABA) in both MDD and primary insomnia (PI). Here, we have utilized single-voxel proton magnetic spectroscopy (1H-MRS) at 4 Tesla to examine GABA relative to total creatine (GABA/Cr) in the occipital cortex (OC), anterior cingulate cortex (ACC), and thalamus in 20 non-medicated adults with PI (12 women) and 20 age- and sex-matched healthy sleeper comparison subjects. PI subjects had significantly lower GABA/Cr in the OC (p=0.0005) and ACC (p=0.03) compared with healthy sleepers. There was no significant difference in thalamic GABA/Cr between groups. After correction for multiple comparisons, GABA/Cr did not correlate significantly with insomnia severity measures among PI subjects. This study is the first to demonstrate regional reductions of GABA in PI in the OC and ACC. Reductions in GABA in similar brain regions in MDD using 1H-MRS suggest a common reduction in cortical GABA among PI and mood disorders.

Absence of changes in GABA concentrations with age and gender in the human anterior cingulate cortex: a MEGA-PRESS study with symmetric editing pulse frequencies for macromolecule suppression

Despite MEGA-PRESS being a robust method for editing the GABA resonance, there are macromolecule resonances at the same chemical shift that are coedited with this sequence. Although this is a known problem, it is still often overlooked. We aimed to evaluate the amount of macromolecule signal coedited, as well as the gender and age dependencies for the GABA resonance at 3.01 ppm using MEGA-PRESS with two different editing pulse frequencies. Forty-five healthy subjects (21-52 years) were included in an in vivo single voxel MEGA-PRESS study at 3.0 T. Phantom measurements were conducted to measure the signal loss when switching the editing pulse between 1.5 and 1.9 ppm instead of the mostly used switching between 1.9 and 7.5 ppm. The in vivo GABA signal detected by switching the editing pulse frequencies between 1.5 and 1.9 ppm was only 50% of the mean GABA detected by switching the editing pulse frequencies between 1.9 and 7.5 ppm. No gender differences were detected. A small age dependency was observed for GABA plus macromolecules, but not for GABA, suggesting an age-dependent macromolecule increase.

Ex vivo detection for chronic ethanol consumption-induced neurochemical changes in rats

The aim of this study was to quantitatively investigate the chronic ethanol-induced cerebral metabolic changes in various regions of the rat brain, using the proton high resolution magic angle spinning spectroscopy technique. The rats were divided into two groups (control group: N=11, ethanol-treated group: N=11) and fed with the liquid diets for 10 weeks. In each week, the mean intake volumes of liquid diet were measured. The brain tissues, including cerebellum (Cere), frontal cortex (FC), hippocampus (Hip), occipital cortex (OC) and thalamus (Thal), were harvested immediately after the end of experiments. The ex vivo proton spectra for the five brain regions were acquired with the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence at 500-MHz NMR spectrometer. All of the spectra were processed using the LCModel software, with simulated basis-set file, and the metabolite levels were referenced to total creatine. In the ethanol liquid diet group, there were significant increases in the metabolites ratio levels, as compared to control (Cere: alanine, glutathione, and N-acetlyaspartate; FC: phosphocholine and taurine; Hip: alanine, glutamine, and N-acetylaspartate; OC: glutamine; Thal: alanine, γ-aminobutyric acid, glutamate, glycerophosphocholine, phosphocholine, taurine, and free choline). However, in the ethanol liquid diet group, the myo-inositol levels of the OC were significantly lower. The present study demonstrates how chronic ethanol consumption affects cerebral metabolites in the chronic ethanol-treated rat. Therefore, this result could be useful to pursue clinical applications for quantitative diagnosis in human alcoholism.