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Early-life sleep deprivation (ESD) is a serious condition with severe metabolic sequelae. The pineal hormone melatonin plays an important role in homeostatic regulation of metabolic function. Considering norepinephrine-mediated Ca(2+) influx and subsequent protein kinase A (PKA) activation is responsible for downstream cAMP-response element-binding protein (CREB) phosphorylation and melatonin biosynthesis, the present study determined whether Ca(2+) expression, together with the molecular machinery participated in melatonin production would significantly alter after ESD. Weaning rats subjected to chronic ESD and maintained naturally (light:dark cycle = 12:12) to adulthood were processed for time-of-flight secondary ion mass spectrometry, immunoblotting, immunohistochemistry together with spectrometric assay to detect the Ca(2+) signaling, adrenoreceptors, PKA, phosphorylated CREB (pCREB) as well as the serum level of melatonin, respectively. Pineal bio-energetics and metabolic function were determined by measuring the cytochrome oxidase activity and serum level of glucose, triglyceride, insulin, high- and low-density lipoproteins, respectively. Results indicated that in normal rats, strong Ca(2+) signaling along with intense adrenoreceptors, PKA, and pCREB activities were all detected in pinealocytes. Enhanced Ca(2+) imaging and signaling pathway corresponded well with intact bio-energetics, normal melatonin production and metabolic activity. However, following ESD, not only Ca(2+) but also pineal signaling activities were all significantly decreased. Blood analysis showed reduced melatonin level and impaired metabolic function after ESD. As depressed Ca(2+)-mediated signaling pathway and melatonin biosynthesis are positively correlated with the development of metabolic dysfunction, supplementary use of melatonin in childhood may thus serve as a practical way to prevent or counteract the ESD-induced metabolic deficiency.

Sleep deprivation causes cognitive dysfunction in which impaired neuronal plasticity in hippocampus may underlie the molecular mechanisms of this deficiency. Considering calcium-mediated NMDA receptor subunit 1 (NMDAR1) and neuronal nitric oxide synthase (nNOS) activation plays an important role in the regulation of neuronal plasticity, the present study is aimed to determine whether total sleep deprivation (TSD) would impair calcium expression, together with injury of the neuronal plasticity in hippocampus. Adult rats subjected to TSD were processed for time-of-flight secondary ion mass spectrometry, NMDAR1 immunohistochemistry, nNOS biochemical assay, cytochrome oxidase histochemistry, and the Morris water maze learning test to detect ionic, neurochemical, bioenergetic as well as behavioral changes of neuronal plasticity, respectively. Results indicated that in normal rats, strong calcium signaling along with intense NMDAR1/nNOS expression were observed in hippocampal regions. Enhanced calcium imaging and neurochemical expressions corresponded well with strong bioenergetic activity and good performance of behavioral testing. However, following TSD, both calcium intensity and NMDAR1/nNOS expressions were significantly decreased. Behavioral testing also showed poor responses after TSD. As proper calcium expression is essential for maintaining hippocampal neuronal plasticity, impaired calcium expression would depress downstream NMDAR1-mediated nNOS activation, which might contribute to the initiation or development of TSD-related cognitive deficiency.

Biological rhythms are a ubiquitous feature of all higher organisms. The rhythmic center of mammals is located in the suprachiasmatic nucleus (SCN), which projects to a number of brainstem centers to exert diurnal control over many physiological processes, including cardiovascular regulation. Total sleep deprivation (TSD) is a harmful condition known to impair cardiovascular activity, but the molecular mechanisms are unknown. As the inward sodium current has long been suggested as playing an important role in driving the spontaneous firing of the SCN, the present study aimed to determine if changes in sodium expression, together with its molecular machinery (Na-K ATPase) and rhythmic activity within the SCN, would occur during TSD. Adult rats subjected to different periods of TSD were processed for time-of-flight secondary ion mass spectrometry, Na-K ATPase assay, and cytochrome oxidase (COX) (an endogenous bioenergetic marker for neuronal activity) histochemistry. Cardiovascular dysfunction was determined through analysis of heart rate and changes in mean arterial pressure. Results indicated that, in normal rats, strong sodium signals were expressed throughout the entire SCN. Enzymatic data corresponded well with spectrometric findings in which high levels of Na-K ATPase and COX were observed in this nucleus. However, following TSD, all parameters including sodium imaging, sodium intensity as well as COX activities were drastically decreased. Na-K ATPase showed an increase in responsiveness following TSD. Both heart rate and mean arterial pressure measurements indicated an exaggerated pressor effect following TSD treatment. As proper sodium levels are essential for SCN activation, reduced SCN sodium levels may interrupt the oscillatory control, which could serve as the underlying mechanism for the initiation or development of TSD-related cardiovascular deficiency., (© 2010 The Authors. Journal of Anatomy © 2010 Anatomical Society of Great Britain and Ireland.)

Sleep disorders are associated with an increased rate of various metabolic disturbances, which may be related to oxidative stress and consequent lipid peroxidation. Since hepatic phosphatidylcholine plays an important role in metabolic regulation, the aim of the present study was to determine phosphatidylcholine expression in the liver following total sleep deprivation. To determine the effects of total sleep deprivation, we used adult rats implanted for polygraphic recording. Phosphatidylcholine expression was examined molecularly by the use of time-of-flight secondary ion mass spectrometry, along with biochemical solid-phase extraction. The parameters of oxidative stress were investigated by evaluating the hepatic malondialdehyde levels as well as heat shock protein 25 immunoblotting and immunohistochemistry. In normal rats, the time-of-flight secondary ion mass spectrometry spectra revealed specific peaks (m/z 184 and 224) that could be identified as molecular ions for phosphatidylcholine. However, following total sleep deprivation, the signals for phosphatidylcholine were significantly reduced to nearly one-third of the normal values. The results of solid-phase extraction also revealed that the phosphatidylcholine concentration was noticeably decreased, from 15.7 micromol g-1 to 9.4 micromol g-1, after total sleep deprivation. By contrast, the biomarkers for oxidative stress were drastically up-regulated in the total sleep deprivation-treated rats as compared with the normal ones (4.03 vs. 1.58 nmol mg-1 for malondialdehyde levels, and 17.1 vs. 6.7 as well as 1.8 vs. 0.7 for heat shock protein 25 immunoblotting and immunoreactivity, respectively). Given that phosphatidylcholine is the most prominent component of all plasma lipoproteins, decreased expression of hepatic phosphatidylcholine following total sleep deprivation may be attributed to the enhanced oxidative stress and the subsequent lipid peroxidation, which would play an important role in the formation or progression of total sleep deprivation-induced metabolic diseases.

Abstract: Excessive calcium influx in chemosensitive neurons of area postrema (AP) is detrimental for sympathetic activation and participates in the disruption of cardiovascular activities. Since total sleep deprivation (TSD) is a stressful condition known to harm the cardiovascular function, the present study is aimed to determine whether the in vivo calcium expression in AP would significantly alter following TSD by the use of time-of-flight secondary ion mass spectrometry (TOF-SIMS) and calretinin (a specific calcium sensor protein in AP neurons) immunohistochemistry. The results indicated that in normal rats, the calcium intensity was estimated to be 0.5×105 at m/z 40.08. However, following TSD, the intensity for calcium ions was greatly increased to 1.2×105. Molecular imaging revealed that after TSD, various strongly expressed calcium signals were distributed throughout AP with clear identified profiles instead of randomly scattered within this region in normal rats. Immunohistochemical staining corresponded well with ionic image in which a majority of calcium-enriched gathering co-localized with calretinin positive neurons. The functional significance of TSD-induced calcium augmentation was demonstrated by increased heart rate and mean arterial pressure, clinical markers for cardiovascular dysfunction. Considering AP-mediated sympathetic activation is important for cardiovascular regulation, exaggerated calcium influx in AP would render this neurocircuitry more vulnerable to over-excitation, which might serve as the underlying mechanism for the development of TSD-relevant cardiovascular deficiency. [Copyright &y& Elsevier]

Abstract: Area postrema (AP) is a circumventricular organ plays an important role in sodium homeostasis and cardiovascular regulation. Since sleep deficiency will cause cardiovascular dysfunction, the present study aims to determine whether sodium level would significantly alter in AP following total sleep deprivation (TSD). Sodium level was investigated in vivo by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Clinical manifestation of cardiovascular function was demonstrated by mean arterial pressure (MAP) values. Results indicated that in normal rats, TOF-SIMS spectrum revealed a major peak of sodium ion counting as 5.61×105 at m/z 23. The sodium ions were homogeneous distributed in AP without specific localization. However, following TSD, the sodium intensity was relatively increased (6.73×105) and the signal for sodium image was strongly expressed throughout AP with definite spatial distribution. MAP of TSD rats is 138±5mmHg, which is significantly higher than that of normal ones (121±3mmHg). Regarding AP is an important area for sodium sensation and development of hypernatremic related sympatho-excitation; up-regulation of sodium expression following TSD suggests that high sodium level might over-activate AP, through complex neuronal networks involving in sympathetic regulation, which could lead to the formation of TSD relevant cardiovascular diseases. [Copyright &y& Elsevier]

Teeth are the hardest tissue in the body. The growth of teeth is closely regulated by circadian rhythmicity. Considering that sleep deprivation (SD) is a severe condition that disrupts normal circadian rhythmicity, this study was conducted to determine whether calcium expression (the major element participating in teeth constitution), and dental mass would be significantly impaired following SD. Adolescent rats subjected to 3 weeks of SD were processed for energy dispersive spectrum (EDS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), and micro-computed tomography (micro-CT) analyses. The EDS and TOF-SIMS results indicated that high calcium intensity was detected in both the upper and lower incisors of untreated rats. Micro-CT analysis corresponded closely with spectral data in which an enhanced dental mass was calculated in intact animals. However, following SD, both calcium expression and the dental mass were remarkably decreased to nearly half those of the untreated values. Because SD plays a detrimental role in impairing dental structure, establishing satisfactory sleep behavior would therefore serve as a crucial strategy for preventing or improving prevalent dental dysfunctions. [ABSTRACT FROM AUTHOR]

Abstract: Sleep disorder is associated with metabolic disturbances, which was related to oxidative stress and subsequently sodium overload. Since liver plays important roles in metabolic regulation, present study is aimed to determine whether hepatic sodium, together with oxidative stress, would significantly alter after total sleep deprivation (TSD). Sodium ion was investigated by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Parameter for oxidative stress was examined by heat shock protein-25 (HSP-25) immunohistochemistry. TOF-SIMS spectrum indicated that hepatic Na+/K+ ratio counting as 82.41±9.5 was obtained in normal rats. Sodium ions were distributed in hepatocytes with several aggregations. However, following TSD, the intensity for Na+/K+ ratio was relatively increased (101.94±6.9) and signals for sodium image were strongly expressed throughout hepatocytes without spatial localization. Quantitative analysis revealed that HSP-25 staining intensity is 1.78±0.27 in TSD rats, which was significantly higher than that of normal ones (0.68±0.15). HSP-25 augmentation suggests that hepatocytes suffer from oxidative stress following TSD. Concerning oxidative stress induced sodium overload would impair metabolic function; enhanced hepatic sodium expression after TSD may be a major cause of TSD relevant metabolic diseases. [Copyright &y& Elsevier]

• PAW significantly increases the solubility of melatonin that endows lipophilic property. • Melatonin dissolved in PAW displays greater anti-viral activity against dengue infection. • PAW plays synergetic effects with melatonin to raise melatonin's anti-oxidative function. • Melatonin dissolved in PAW greatly improves hepatic bioenergetics after sleep deprivation. • PAW may act as a powerful medium to greatly enhance melatonin's therapeutic efficiency. Melatonin is a lipophilic antioxidant generally dissolved in organic solvent before delivery. However, the presence of organics may severely depress the functional effects of melatonin. By rendering deionized water (DIW) flow through gold nano-particles under localized surface plasmon resonant illumination, we developed plasmon-activated water (PAW) which successfully increases the solubility of melatonin to 150.325%. Melatonin dissolved in PAW also exhibits stronger anti-viral and anti-oxidative activities than that dissolved in DIW in which the percentage of dengue virus infected human hepatocellular carcinoma cells is remarkably decreased (14.7% vs. 20.6%) whilst the clearance rate of hydroxyl radical is significantly enhanced (11.9% vs. 6.69%), respectively. Moreover, in vivo approaches further show that following chronic sleep deprivation, the level of oxidative stress, hepatic bioenergetics, anti-oxidative enzyme activity, and metabolic function are all significantly improved in rats received melatonin prepared in PAW than that in DIW. As the bio-activity of melatonin depends largely on its solubility, utilizing PAW as a non-organic solvent will not only enhance the anti-viral and anti-oxidative function of melatonin, but also offer great potential for clinical use of melatonin as a therapeutic strategy to depress virus infection and counteract oxidative damage in a more natural, more economic and more efficient way. [ABSTRACT FROM AUTHOR]