Adults Who Are Overweight or Obese and Consuming an Energy-Restricted Healthy US-Style Eating Pattern at Either the Recommended or a Higher Protein Quantity Perceive a Shift from "Poor" to "Good" Sleep: A Randomized Controlled Trial.

BACKGROUND: Limited evidence suggests that consuming a higher-protein diet during weight loss improves subjective indices of sleep in overweight and obese adults. OBJECTIVE: We sought to a priori assess the effects of consuming the recommended versus a higher protein Healthy US-Style Eating Pattern during energy-restriction on sleep quality indices. DESIGN: Using a randomized, parallel study design, 51 adults (mean ± SEM age: 47 ± 1 y; BMI: 32.6 ± 0.5 kg/m2) consumed a controlled USDA Healthy US-Style Eating Pattern containing 750 kcal/d less than their estimated energy requirement for 12 wk. Participants were randomly assigned to consume either 5 or 12.5 oz-equivalent (eq)/d of protein foods. The additional 7.5 oz-eq/d came from animal-based protein sources and displaced primarily grains. Objective (wrist-worn actigraphy) and subjective (Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale) sleep quality indices were measured at baseline, week 6, and week 12. RESULTS: Among all participants, body mass decreased (-6.2 ± 0.4 kg). Dietary protein intake did not affect any objective or subjective sleep quality outcomes measured (repeated measures ANOVA). Over time, objective measures of time spent in bed, time spent sleeping, sleep onset latency, and time awake after sleep onset did not change; however, sleep efficiency improved (1 ± 1%; P = 0.027). Subjectively, global sleep scores [GSS: -2.7 ± 0.4 arbitrary units (au)] and daytime sleepiness scores (-3.8 ± 0.4 au; both P < 0.001) improved over time. The GSS improvement transitioned the participants from being categorized with "poor" to "good" sleep (GSS: >5 compared with ≤5 au of a 0-21 au scale; baseline 7.6 ± 0.4 au, week 12: 4.8 ± 0.4 au). CONCLUSIONS: Although objective sleep quality may not improve, adults who are overweight or obese and poor sleepers may become good sleepers while consuming either the recommended or a higher-protein energy-restricted Healthy US-Style Eating Pattern. This trial was registered at clinicaltrials.gov as NCT03174769.

GABAergic signaling in the rat pineal gland.

Pinealocytes secrete melatonin at night in response to norepinephrine released from sympathetic nerve terminals in the pineal gland. The gland also contains many other neurotransmitters whose cellular disposition, activity, and relevance to pineal function are not understood. Here, we clarify sources and demonstrate cellular actions of the neurotransmitter γ-aminobutyric acid (GABA) using Western blotting and immunohistochemistry of the gland and electrical recording from pinealocytes. GABAergic cells and nerve fibers, defined as containing GABA and the synthetic GAD67, were identified. The cells represent a subset of interstitial cells while the nerve fibers were distinct from the sympathetic innervation. The GABAA receptor subunit α1 was visualized in close proximity of both GABAergic and sympathetic nerve fibers as well as fine extensions among pinealocytes and blood vessels. The GABAB 1 receptor subunit was localized in the interstitial compartment but not in pinealocytes. Electrophysiology of isolated pinealocytes revealed that GABA and muscimol elicit strong inward chloride currents sensitive to bicuculline and picrotoxin, clear evidence for functional GABAA receptors on the surface membrane. Applications of elevated potassium solution or the neurotransmitter acetylcholine depolarized the pinealocyte membrane potential enough to open voltage-gated Ca(2+) channels leading to intracellular calcium elevations. GABA repolarized the membrane and shut off such calcium rises. In 48-72-h cultured intact glands, GABA application neither triggered melatonin secretion by itself nor affected norepinephrine-induced secretion. Thus, strong elements of GABA signaling are present in pineal glands that make large electrical responses in pinealocytes, but physiological roles need to be found.

Effects of milking frequency in automatic milking systems on salivary cortisol, immunoglobulin A, somatic cell count and melatonin.

INTRODUCTION: In barns with an automatic milking system (AMS), both the milking frequency and the number of nighttime milkings vary between cows. A low milking frequency might indicate problems in gaining access to the milking unit. Also, nighttime lighting in the waiting area of the AMS and in the milking unit increases exposure to light at night and could suppress nocturnal melatonin synthesis. These effects could result in increased stress, suppressed immune response, and poor udder health. A total of 125 cows (14-16/farm) on 8 farms with AMS were selected based on their average milking frequency. Eight to 10 saliva samples per cow were taken over the course of 4 days, and cortisol, IgA and melatonin concentrations were determined. Somatic cell counts (SCC) were determined in milk samples. Milking frequency had no significant relationship with mean cortisol and IgA levels, but a higher milking frequency tended to be associated with lower SCC levels. Nocturnal melatonin levels tended to be negatively associated with the number of nighttime milkings. In conclusion, no indication of increased stress or reduced immune defense was found in relation to milking frequency on farms with an AMS.

INTRODUCTION: Dans les étables équipées d'un système de traite automatique, la fréquence ainsi que le nombre de traites nocturnes varient d'une vache à l'autre. Une fréquence basse pourrait être le signe de difficultés d'accès à l'unité de traite. D'autre part, l'éclairage dans la zone d'attente et dans l'unité de traite expose les vaches à plus de lumière durant la nuit, ce qui pourrait réduire la sécrétion de mélatonine. Ces éléments pourraient amener un stress et avoir une influence sur la réponse immunitaire et la santé de la mamelle. Pour la présente étude, 125 vaches provenant de 8 exploitations (14­16 animaux par exploitation) ont été choisies en fonction de leur fréquences de traite. On a prélevé 8 à 10 échantillons de salive sur une période de 4 jours et y a mesuré la concentration de cortisol, d'IgA et de mélatonine. On n'observe pas de rapport significatif entre la fréquence de traite et les concentrations moyennes de cortisol et d'IgA mais une fréquence de traite plus élevée a tendance à être corrélée avec un nombre de cellules plus faible. Les concentrations de mélatonine durant la nuit avait tendance à être associées de façon négative avec le nombre de traites nocturnes. De façon générale, on n'a pas d'indice montrant un stress plus élevé ou une réduction de la réponse immunitaire en fonction de la fréquence de traite dans les exploitations équipées d'un système de traite automatique.

Is melatonin as an ergogenic hormone a myth? a systematic review and meta-analysis.

PURPOSE: Melatonin supplementation has been disclosed as an ergogenic substance. However, the effectiveness of melatonin supplementation in healthy subjects has not been systematically investigated. The present study analyzed the effects of melatonin supplementation on physical performance and recovery. In addition, it was investigated whether exercise bout or training alter melatonin secretion in athletes and exercise practitioners. METHODS: This systematic review and meta-analysis were conducted and reported according to the guidelines outlined in the PRISMA statement. Based on the search and inclusion criteria, 21 studies were included in the systematic review, and 19 were included in the meta-analysis. RESULTS: Melatonin supplementation did not affect aerobic performance relative to time trial (-0.04; 95% CI: -0.51 to 0.44) and relative to VO2 (0.00; 95% CI: -0.57 to 0.57). Also, melatonin supplementation did not affect strength performance (0.19; 95% CI: -0.28 to 0.65). Only Glutathione Peroxidase (GPx) secretion increased after melatonin supplementation (1.40; 95% CI: 0.29 to 2.51). Post-exercise melatonin secretion was not changed immediately after an exercise session (0.56; 95% CI: -0.29 to 1.41) and 60 min after exercise (0.56; 95% CI: -0.29 to 1.41). CONCLUSION: The data indicate that melatonin is not an ergogenic hormone. In contrast, melatonin supplementation improves post-exercise recovery, even without altering its secretion.

CircRNA-WNK2 Acts as a ceRNA for miR-328a-3p to Promote AANAT Expression in the Male Rat Pineal Gland.

Noncoding RNAs (ncRNAs), including microRNAs (miRNAs) and circular RNAs (circRNAs), which are expressed with a daily rhythm in the rat pineal gland, are associated with the regulation of melatonin secretion and other biological functions. However, the mechanisms of these molecules in the rat pineal gland are not yet fully understood. In this study, we found that circR-WNK2 was highly expressed at night, which may be involved in the regulation of melatonin secretion through the competitive endogenous RNA (ceRNA) mechanism. By dual luciferase reporter, RNA pull-down, and fluorescence in situ hybridization (FISH) assays, we found that miR-328a-3p can target circR-WNK2 and the Aa-nat mRNA 3'UTR. Transfection experiments indicated that circR-WNK2 could competitively bind to miR-328a-3p, reduce miR-328a-3p expression, and promote Aa-nat gene expression and melatonin secretion. And by constructing a superior cervical ganglionectomy (SCGx) rat model, we found that ncRNAs expression in the pineal gland was regulated by signals from the suprachiasmatic nucleus. This finding supports the hypothesis that these noncoding RNAs may interact to shape the circadian rhythm through transcriptional processing in melatonin synthesis.

Transcutaneous auricular vagal nerve stimulation releases extrapineal melatonin and reduces thermal hypersensitivity in Zucker diabetic fatty rats.

Type 2 diabetes (T2D) is the most common comorbidity of COVID-19, and both are related to the lack of circulating melatonin. In addition, chronic pain is a common sequela of both COVID-19 and T2D. Using a neuropathic pain model produced by sciatic nerve chronic constriction injury in Zucker diabetic fatty rats, a verified preclinical genetic T2D neuropathy animal model, this study aimed to show that transcutaneous auricular vagal nerve stimulation (taVNS) could elevate plasma melatonin concentration, upregulate the expression of melatonin receptors (MTRs) in the amygdala, and relieve peripheral neuropathic pain. Furthermore, taVNS would restore melatonin levels and relieve pain even in pinealectomized rats. On the contrary, intraperitoneally injected luzindole, a melatonin receptor antagonist, would attenuate the antinociceptive effects of taVNS. In conclusion, the mechanism of the therapeutic effect of taVNS on chronic pain involves the release of extrapineal melatonin and the positive regulation of the expression of central MTRs. This beneficial efficacy should be considered during COVID-19 rehabilitation in individuals with diabetes.

Effects of Photoperiod Change on Melatonin Secretion, Immune Function and Antioxidant Status of Cashmere Goats.

The photoperiod affects animals' secretion of hormones, especially melatonin (MLT), which is involved in the regulation of the immune function and antioxidant status. The present experiment was conducted to study the effects of the photoperiod on MLT secretion, immune function, antioxidant status and related gene expression in goats. Eighteen adult female cashmere goats were randomly divided into three photoperiod groups: the control group (CG: natural photoperiod); the short-day photoperiod group (SDPP group: 8 h light; 16 h dark) and the shortening-day photoperiod group (SIPP group: lighting time shortened gradually from 16 h/d to 8 h/d). The experiment lasted for 60 days. The results showed that SDPP increased MLT concentration in serum at day 30 of the experiment (p < 0.05), but SIPP increased it at day 60 (p < 0.05). The activity of total superoxide dismutase (T-SOD), glutathione peroxidase (GPx) and catalase (CAT) increased (p < 0.05), and malondialdehyde (MDA) concentration decreased (p < 0.05) at day 30 in SDPP; no significant effects of SIPP were observed at day 30. Both SDPP and SIPP goats had higher activities of T-SOD, GPx and CAT (p < 0.05) at day 60. The concentration of immunoglobulin G (IgG), interleukin 1ß (IL-1ß) and interleukin 2 (IL-2) increased in SDPP (p < 0.05) at day 30. Both SDPP and SIPP raised the concentration of IgG, IL-1ß and IL-2 at day 60 (p < 0.05). For the relative gene expression, the SDPP improved the gene expression of SOD1, CAT, GPx4, nuclear factor erythroid-2-related factor 2(Nrf2), IL-1ß, IL-2 and tumor necrosis factor-α (TNF-α) (p < 0.05) in blood leukocytes at day 30. In addition, at day 60, goats in the SDPP group had a higher gene expression of CAT, GPx4, IL-1ß and IL-2 (p < 0.05). Goats in SIPP had significantly higher gene expression of SOD1, CAT, GPx4, Nrf2, TNFα, IL-1ß and IL-2 (p < 0.05) than those in CG. These results indicated that SDPP and SIPP could secrete more MLT and then improve the immune function and antioxidant status of the goats.

Non-visual effects of diurnal exposure to an artificial skylight, including nocturnal melatonin suppression.

BACKGROUND: Recently, more consideration is being given to the beneficial effects of lighting on the maintenance and promotion of the health and well-being of office occupants in built environments. A new lighting technology using Rayleigh scattering has made it possible to simulate a blue sky. However, to date, no studies have examined the possible beneficial effects of such artificial skylights. The aims of this study were to examine the non-visual effects of artificial skylights and conventional fluorescent lights in a simulated office environment and to clarify the feature effects of the artificial skylights. METHODS: Participants were 10 healthy male adults. Non-visual effects were evaluated based on brain arousal levels (α-wave ratio and contingent negative variation [CNV]), autonomic nervous activity (heart rate variability [HRV]), work performance, and subjective responses during daytime exposure to either an artificial skylight or fluorescent lights, as well as nocturnal melatonin secretion. RESULTS: Subjective evaluations of both room lighting-related "natural" and "attractive" items and the "connected to nature" item were significantly higher with the skylight than with the fluorescent lights. Cortical arousal levels obtained from the early component of the CNV amplitude were significantly lower with the skylight than with the fluorescent lights, whereas α-wave ratio and work performance were similar between the two light sources. The HRV evaluation showed that sympathetic nerve tone was lower and parasympathetic nerve tone was higher, both significantly, for the skylight than for the fluorescent lights during daytime. Nocturnal melatonin secretion was significantly greater before and during light exposure at night under the daytime skylight than under the fluorescent lights. CONCLUSIONS: Our results suggest that artificial skylights have some advantages over conventional fluorescent lights in maintaining ordinary work performance during daytime with less psychological and physiological stress. The findings also suggest that the artificial skylights would enable built environments to maintain long-term comfort and productivity.