Noradrenaline enhances Na-K ATPase subunit expression by HuR-induced mRNA stabilization and their transportation to the cell surface through PLC and PKC mediated pathway: Implications with REMS-loss associated disorders.

Rapid eye movement sleep (REMS) maintains brain excitability at least by regulating Na-K ATPase activity. Although REMS deprivation (REMSD)-associated elevated noradrenaline (NA) increases Na-K ATPase protein expression, its mRNA transcription did not increase. We hypothesized and confirmed both in vivo as well as in vitro that elevated mRNA stability explains the apparent puzzle. The mRNA stability was measured in control and REMSD rat brain with or without in vivo treatment with α1-adrenoceptor (AR) antagonist, prazosin (PRZ). Upon REMSD, Na-K ATPase α1-, and α2-mRNA stability increased significantly, which was prevented by PRZ. To decipher the molecular mechanism of action, we estimated NA-induced Na-K ATPase mRNA stability in Neuro-2a cells under controlled conditions and by transcription blockage using Actinomycin D (Act-D). NA increased Na-K ATPase mRNA stability, which was prevented by PRZ and propranolol (PRP, ß-AR antagonist). The knockdown assay confirmed that the increased mRNA stabilization was induced by elevated cytoplasmic abundance of Human antigen R (HuR) and involving (Phospholipase C) PLC-mediated activation of Protein Kinase C (PKC). Additionally, using cell-impermeable Enz-link sulfo NHS-SS-Biotin, we observed that NA increased Na-K ATPase α1-subunits on the Neuro-2a cell surface. We conclude that REMSD-associated elevated NA, acting on α1- and ß-AR, increases nucleocytoplasmic translocation of HuR and increases Na-K ATPase mRNA stability, resulting in increased Na-K ATPase protein expression. The latter then gets translocated to the neuronal membrane surface involving both PKC and (Protein Kinase A) PKA-mediated pathways. These findings may be exploited for the amelioration of REMSD-associated chronic disorders and symptoms.

Proteomics in Human Parkinson's Disease: Present Scenario and Future Directions.

Parkinson's disease (PD) is an age-related, threatening neurodegenerative disorder with no reliable treatment till date. Identification of specific and reliable biomarker is a major challenge for disease diagnosis and designing effective therapeutic strategy against it. PD pathology at molecular level involves abnormal expression and function of several proteins, including alpha-synuclein. These proteins affect the normal functioning of neurons through various post-translational modifications and interaction with other cellular components. The role of protein anomalies during PD pathogenesis can be better understood by the application of proteomics approach. A number of proteomic studies conducted on brain tissue, blood, and cerebrospinal fluid of PD patients have identified a wide array of protein alterations underlying disease pathogenesis. However, these studies are limited by the types of brain regions or biofluids utilized in the research. For a complete understanding of PD mechanism and discovery of reliable protein biomarkers, it is essential to analyze the proteome of different PD-associated brain regions and easily accessible biofluids such as saliva and urine. The present review summarizes the major advances in the field of PD research in humans utilizing proteomic techniques. Moreover, potential samples for proteomic analysis and limitations associated with the analyses of different types of samples have also been discussed.

REM Sleep Loss-Induced Elevated Noradrenaline Plays a Significant Role in Neurodegeneration: Synthesis of Findings to Propose a Possible Mechanism of Action from Molecule to Patho-Physiological Changes.

Wear and tear are natural processes for all living and non-living bodies. All living cells and organisms are metabolically active to generate energy for their routine needs, including for survival. In the process, the cells are exposed to oxidative load, metabolic waste, and bye-products. In an organ, the living non-neuronal cells divide and replenish the lost or damaged cells; however, as neuronal cells normally do not divide, they need special feature(s) for their protection, survival, and sustenance for normal functioning of the brain. The neurons grow and branch as axons and dendrites, which contribute to the formation of synapses with near and far neurons, the basic scaffold for complex brain functions. It is necessary that one or more basic and instinct physiological process(es) (functions) is likely to contribute to the protection of the neurons and maintenance of the synapses. It is known that rapid eye movement sleep (REMS), an autonomic instinct behavior, maintains brain functioning including learning and memory and its loss causes dysfunctions. In this review we correlate the role of REMS and its loss in synaptogenesis, memory consolidation, and neuronal degeneration. Further, as a mechanism of action, we will show that REMS maintains noradrenaline (NA) at a low level, which protects neurons from oxidative damage and maintains neuronal growth and synaptogenesis. However, upon REMS loss, the level of NA increases, which withdraws protection and causes apoptosis and loss of synapses and neurons. We propose that the latter possibly causes REMS loss associated neurodegenerative diseases and associated symptoms.

Prevalence of VKORC1 and CYP2C9 gene polymorphisms in Indian population and its effect on warfarin response.

OBJECTIVES: The clinical effectiveness of Warfarin is established. Patients require different warfarin dosages to achieve the target therapeutic anticoagulation. The variability of Warfarin dosage is largely genetically determined, and it can be partly explained by the C1173T and G-1639A polymorphisms of vitamin K epoxide reductase complex subunit 1 (VKORC1) which is its target and *2 and *3 allele of Cytochrome P-450 (CYP) 2C9 [CYP2C9] enzyme which metabolizes to its inactive form. Aim of the present study was to determine the prevalence of these variant alleles known to influence the warfarin dose and correlate genotypes with the average INR as well as mean dose of Warfarin required to maintain INR, in the Indian population. METHODS: Study population included 100 healthy individuals and 83 patients operated for Aortic or Mitral Valve replacement and prescribed warfarin thereafter. Of these 83 patients records of INR for the period of six months and mean maintenance dose (stable therapeutic dose) of warfarin required to maintain INR were available for 26 patients. For the remaining patients, apart from their demographic data only maintenance dose was available. Genotyping of above mentioned polymorphisms was carried out by using PCR-based restriction digestion method. RESULTS: Although less as compared to wild type alleles, the variant alleles of CYP2C9*2 and *3 as well as of VKORC1 polymorphisms (C1173T and G-1639A) were observed in our study population. Mean maintenance dose (mg/day) of Warfarin was in the decreasing order of patients as compared to the wild type genotypes for all above mentioned polymorphisms. The decrease in the dose was in the order of heterozygotes for CYP2C9*2 to CYP2C9*3 to C1173T and G-1639A of VKORC1 (P<0.001). There was significant correlation (r=0.51, P<0.001) observed between the dose estimated by pharmacogenetic algorithm of Sconce et al (2005) and actual stable therapeutic dose. INR was high for mutant variants (3.8 to 4) after first dose suggesting that they require decreased mean daily dose of Warfarin. CONCLUSION: In the present study the effect of CYP2C9*2, *3, and VKORC1 (C1173T and G-1639A) genotypes on warfarin dose was observed. However, the genotyping has not been incorporated into daily practice. Perhaps more practical approach would be for clinicians to take genotype information into consideration along with other factors when dosing warfarin.

Sleep and Neuroimmunomodulation for Maintenance of Optimum Brain Function: Role of Noradrenaline.

Immune function and sleep are two normal physiological processes to protect the living organism from falling sick. There is hardly any disease in which they remain unaffected, though the quantum of effect may differ. Therefore, we propose the existence of a strong correlation between sleep (quality or quantity) and immune response. This may be supported by the fact that sleep loss modulates many of the immunological molecules, which includes interferons; however, not much is known about their mechanism of action. Sleep is divided into rapid eye movement sleep (REMS) and non-REMS. For practical reasons, experimental studies have been conducted mostly by inducing loss of REMS. It has been shown that withdrawal of noradrenaline (NA) is a necessity for generation of REMS. Moreover, NA level increases in the brain upon REMS loss and the elevated NA is responsible for many of the sleep loss-associated symptoms. In this review, we describe how sleep (and its disturbance/loss) modulates the immune system by modulating the NA level in the brain or vice versa to maintain immune functions, physiological homeostasis, and normal healthy living. The increased levels of NA during REMS loss may cause neuroinflammation possibly by glial activation (as NA is a key modulator of microglia). Therefore, maintaining sleep hygiene plays a crucial role for a normal healthy living.

The impact of COVID-19 lockdown on mental health: A study from rural population of Haryana, India.

Introduction: COVID-19 (Coronavirus Disease 2019) is a disease caused by a virus named SARS-CoV-2 and was discovered in December 2019 in Wuhan, China, a global threat has largely affected the country's economic and social values. Moreover, the mitigation strategies being used to counterattack the pandemic attributes a lot of unrest and stress in the masses which has led to several mental health problems like anxiety, depression, sleep loss, post-traumatic stress disorder, etc. Objective: In this study, the impact of lockdown on mental health and its related disorders was observed. Method: A total of 367 patients from 69 villages of Narwana sub-division, Haryana, India was included in this study and their mental health status was assessed using Beck's Depression Inventory (BDI). Results: Out of the 367 mental health-related patients, half of them (~ 48%) showed the signs of depression ranging from mild to severe. Also, 40% of the patients showed signs and symptoms of anxiety, fear and stress and (~15%) showed signs of sleep loss. Women (~58%) were significantly found to be more prone to mental illness and psychiatric disorders than men (~42%). This study also reports the increase in domestic violence cases during the lockdown period. The study presents a clear understanding that although lockdown and social isolation helps in achieving the goal of reducing infections, a restricted access of social support systems leads to loneliness and various mental issues including anxiety and depression. Conclusion: We conclude that COVID-19 is a big threat to women safety and health especially in rural population and as the crisis evolves and continues, it is very essential to raise awareness and psychological counseling among the masses.

Receptive and Expressive Language in Hindi Speaking Children with Postcochlear Implantation at 6-Month Intervals.

Introduction Individual variability in the language outcomes of children with cochlear implantation (CI) is a major concern. In CI rehabilitation, there is lack of a protocol regarding uniform post-CI language assessment interval duration, which can ensure better understanding of the trajectory of language growth as well as optimize language outcomes by providing feedback in fine tuning the language intervention program. Objective To evaluate the receptive and expressive language in Hindi speaking children with up to 2 years of CI experience using revised receptive-expressive emergent language test-3ed. (REELT-3) at 6 months intervals and to compare it with that of children with normal hearing (NH). Methods The present study included 192 children divided in 2 groups, 96 children with CI (15.8 ± 6.7 months), and 96 age-matched children with NH (22.3 ± 7.9 months). A cross-sectional, prospective study design was used to measure the language ability score (LAS) at an interval of 6 months from the time of implantation (TIA), which is 0 to 6 months, 7 to 12 months, 13 to 18 months, and 19 to 24 months of CI usage. Results The two-way analysis of variance revealed that the LAS after 18 months of CI usage was similar to (F (3, 92) = 8.63, p = 0.19, ηp2 = 0.028) that of the children with NH. However, other demographic factors, for instance, gender (F (3, 92) = 1.73, p = 0.505, ηp2 = 0.002), parent's education, (F (3, 92) = 2.05, p = 0.937, ηp2 = 0.031), and financial background (F (3, 92) = 2.49, p = 0.351, ηp2 = 0.076) had no major impact on language. Conclusion Eighteen months of CI usage duration can potentially stimulate receptive and expressive language up to age-matched children with NH. A protocol of periodic assessment of language, at least of 6 months, may be developed to optimize language outcomes.

Diagnostic comparison of biochemical profile in patients with Covid-19, dengue and Acute Febrile illness: Implications for patient management.

PURPOSE: Although there are specific laboratory tests available for the diagnosis of Covid-19 and dengue, during the present pandemic era of prioritized focus on Covid-19 assessment, there are possibilities that persons with dengue may remain undiagnosed. The present study explores the role of biochemical markers in the differential diagnosis of Covid-19 and dengue. METHODS: A total of 212 participants with Acute Febrile Illness were tested for Covid-19 and dengue at the secondary care hospital, Civil Hospital Narwana, Haryana, India. The Covid-19 and dengue diagnosis were performed using standard tests followed by hematological profiling which included neutrophil lymphocyte ratio (NLR), platelet count, Vitamin D3 assessment, SGOT, SGPT, and SPO2 concentration levels. RESULTS: Out of 212 participants, 118 were diagnosed with Covid-19 positive only, 18 dengue positive only, 5 co-infected with Covid-19 and dengue, and 71 persons with Acute Febrile Illness (control group). ANOVA revealed that mean SPO2 was significantly lower in Covid-19 and dengue than control, while SGPT and SGOT levels of Covid-19 and dengue patients were significantly higher than the control group. The mean NLR was significantly higher in Covid-19 and dengue than control and Vitamin D3 levels were significantly reduced for Covid-19 patients. Besides, thrombocytopenia was observed only in dengue patients. CONCLUSION: The results advocate the potential use of combinations of these makers in differential diagnosis of these two fatal viral conditions and can help by enabling the adaptation of the therapeutic conduct to the needs of individual patients.

Adaptation and validation of receptive expressive emergent Language Test-3: Evidence from Hindi speaking children with cochlear implant.

INTRODUCTION: Selection of an effective tool for assessment of language learning outcomes in post cochlear implantation is always an important but challenging task. Receptive expressive emergent language test-3rd Eds. (REELT-3) is one of the comprehensive language assessment tools used in India. In case of administration of REELT-3, which is standardized in English speaking typically developing western population, to another language speaking population with post-cochlear implant condition, the test outcome may get compromised owing to linguistics and population variability. The objective of the study is to test and validate REELT-3 in Hindi speaking children with cochlear implantation. METHODS: Ninety six typically developing children (22.3 ± 6.9 months, 48 boys and 48 girls) and 96 children with cochlear implantation (25.8 ± 9.2 months, 57 boys and 39 girls) participated in this study. As per the eligibility criteria of REELT-3, infants and toddlers with cochlear implant of age below 36 months participated in this study. Criterion, content and construct validity were tested using correlation based statistical analysis. RESULTS: High content validity was established by obtaining very low correlation coefficient r = 0.16 across two distinct population of typically developing children and children with cochlear implantation. Similarly, correlation coefficient of r = 0.84 revealed high criterion validity across REELT-3 in English and Hindi speaking conditions. Finally, correlation coefficient of r = 0.87was obtained between language raw score and chronological age to establish construct validity. Chronbach alpha coefficient (Chronbach α = 0.85) and interclass correlation coefficient 0.87was observed for REELT-3 which suggests good internal consistency and test-retest reliability, respectively. Receiver Operating Characteristics curve analysis of the REELT-3 suggested that area under curve 0.95 (95% CI = 0.89-0.99, p < 0.001) is excellent. The cut-off Language Ability Score (LAS) was determined as 74.5 with the sensitivity of 87.9% and specificity of 84.1% infer high sensitivity and specificity. CONCLUSIONS: These results validate that REELT-3 can be used in assessment of language outcome in Hindi speaking children with post-cochlear implantation. Clinical assessment of receptive and expressive language will be beneficial in effective evaluation as well as in therapeutic planning.

The neuroprotective effect of curcumin against Cd-induced neurotoxicity and hippocampal neurogenesis promotion through CREB-BDNF signaling pathway.

Heavy metal neurotoxicity is one of the major challenges in today's era due to the large scale and widespread mechanisation of the production. However, the causative factors responsible for neurotoxicity are neither known nor do we have the availability of therapeutic approaches to deal with it. One of the major causative agents of neurotoxicity is a non-essential transition heavy metal, Cadmium (Cd), that reaches the central nervous system (CNS) through the nasal mucosa and olfactory pathway causing adverse structural and functional effects. In this study, we explored the neuroprotective efficacy of plant derived Curcumin which is reported to have pleiotropic biological activity including anti-oxidant, anti-inflammatory, anti-apoptotic, anti-carcinogenic and anti-angiogenic effects. Four different concentrations of curcumin (20, 40, 80 and 160 mg/kg of the body weight) were used to assess the behavioural, biochemical, hippocampal proteins (BDNF, CREB, DCX and Synapsin II) and histological changes in Swiss Albino mice that were pre-treated with Cd (2.5 mg/kg). The findings showed that Cd exposure led to the behavioural impairment through oxidative stress, reduction of hippocampal neurogenesis associated proteins, and degeneration of CA3 and cortical neurons. However, treatment of different curcumin concentrations had effectively restored the behavioural changes in Cd-exposed mice through regulation of oxidative stress and up-regulation of hippocampal proteins in a dose-dependent manner. Significantly, a dose of 160 mg/kg body weight was found to be glaringly effective. From this study, we infer that curcumin reverses the adverse effects of neurotoxicity induced by Cd and promotes neurogenesis.

REM sleep loss-induced elevated noradrenaline could predispose an individual to psychosomatic disorders: a review focused on proposal for prediction, prevention, and personalized treatment.

Historically and traditionally, it is known that sleep helps in maintaining healthy living. Its duration varies not only among individuals but also in the same individual depending on circumstances, suggesting it is a dynamic and personalized physiological process. It has been divided into rapid eye movement sleep (REMS) and non-REMS (NREMS). The former is unique that adult humans spend the least time in this stage, when although one is physically asleep, the brain behaves as if awake, the dream state. As NREMS is a pre-requisite for appearance of REMS, the latter can be considered a predictive readout of sleep quality and health. It plays a protective role against oxidative, stressful, and psychopathological insults. Several modern lifestyle activities compromise quality and quantity of sleep (including REMS) affecting fundamental physiological and psychopathosomatic processes in a personalized manner. REMS loss-induced elevated brain noradrenaline (NA) causes many associated symptoms, which are ameliorated by preventing NA action. Therefore, we propose that awareness about personalized sleep hygiene (including REMS) and maintaining optimum brain NA level should be of paramount significance for leading physical and mental well-being as well as healthy living. As sleep is a dynamic, multifactorial, homeostatically regulated process, for healthy living, we recommend addressing and treating sleep dysfunctions in a personalized manner by the health professionals, caregivers, family, and other supporting members in the society. We also recommend that maintaining sleep profile, optimum level of NA, and/or prevention of elevation of NA or its action in the brain must be seriously considered for ameliorating lifestyle and REMS disturbance-associated dysfunctions.

Dim Light at Night Induced Neurodegeneration and Ameliorative Effect of Curcumin.

It is a well-known fact that following a proper routine light/dark or diurnal rhythm controls almost all biological processes. With the introduction of modern lighting and artificial illumination systems, continuous exposure to light at night may lead to the disruption of diurnal rhythm. However, the effect of light during the night on brain anatomy, physiology, and human body functions is less explored and poorly understood. In this study, we have evaluated the effect of exposure to dim light (5 lux) at night (dLAN) on Swiss Albino mice over a duration of three consecutive weeks. Results have revealed that exposure to dLAN led to an impairment of cognitive and non-cognitive behaviour, oxidative stress-mediated elevation of lipid peroxidation, and reduction of superoxide dismutase and catalase activity. It also led to the downregulation of hippocampal proteins (BDNF, Synapsin II and DCX) at both protein and mRNA level. Additionally, there was downregulation of CREB and SIRT1 mRNAs and neurodegeneration-associated miRNA21a-5p and miRNA34a-5p. The pyramidal and cortical neurons started showing pyknotic and chromatolysis characteristics. However, a dose of curcumin administered to the mice positively modulated these parameters in our experimental animals. We proposed the modulatory role of curcumin in addressing the deleterious effects of dLAN.

Relevance of deprivation studies in understanding rapid eye movement sleep.

Rapid eye movement sleep (REMS) is a unique phenomenon essential for maintaining normal physiological processes and is expressed at least in species higher in the evolution. The basic scaffold of the neuronal network responsible for REMS regulation is present in the brainstem, which may be directly or indirectly influenced by most other physiological processes. It is regulated by the neurons in the brainstem. Various manipulations including chemical, elec-trophysiological, lesion, stimulation, behavioral, ontogenic and deprivation studies have been designed to understand REMS genesis, maintenance, physiology and functional significance. Although each of these methods has its significance and limitations, deprivation studies have contributed significantly to the overall understanding of REMS. In this review, we discuss the advantages and limitations of various methods used for REMS deprivation (REMSD) to understand neural regulation and physiological significance of REMS. Among the deprivation strategies, the flowerpot method is by far the method of choice because it is simple and convenient, exploits physiological parameter (muscle atonia) for REMSD and allows conducting adequate controls to overcome experimental limitations as well as to rule out nonspecific effects. Notwithstanding, a major criticism that the flowerpot method faces is that of perceived stress experienced by the experimental animals. Nevertheless, we conclude that like most methods, particularly for in vivo behavioral studies, in spite of a few limitations, given the advantages described above, the flowerpot method is the best method of choice for REMSD studies.

Reciprocal changes in noradrenaline and GABA levels in discrete brain regions upon rapid eye movement sleep deprivation in rats.

Rapid eye movement sleep (REMS) plays important role in maintenance of normal brain functions. Neurons containing various neurotransmitters in different brain regions interact to regulate this complex phenomenon in health and diseases. The number of neuronal projections, their firing rates and neurotransmitter levels vary in different brain regions under various conditions leading to normal or altered patho-physio-behavioral states. In this study using high performance liquid chromatography (HPLC) we quantified noradrenaline (NA) and gamma-amino butyric acid (GABA) levels in locus coeruleus (LC), dorsal raphe (DR), pedunculo-pontine tegmentum (PPT), frontal lobe (FL), cortex and hippocampus (Hippo) in control and after 96 h REMS deprivation (REMSD) rats. Normal free moving control (FMC) rats were taken as standard cage controls. To rule out non-specific effects large platform control (LPC) and post-REMSD recovery (REC) were carried out. The levels of NA and GABA in discrete brain regions upon REMSD were statistically compared with all the controls. Upon REMSD, although NA levels significantly increased and the GABA levels decreased in the LC, PPT and cortex, in Hippo their levels showed opposite responses. Only NA levels increased in FL, while only GABA levels were decreased in the DR after REMSD. Most of the altered neurotransmitter levels returned to normal levels in REC rats. The findings help understanding the neurochemical basis of REMSD and its associated effects.

Receptive and Expressive Language in Hindi Speaking Children with Postcochlear Implantation at 6-Month Intervals

Abstract Introduction Individual variability in the language outcomes of children with cochlear implantation (CI) is a major concern. In CI rehabilitation, there is lack of a protocol regarding uniform post-CI language assessment interval duration, which can ensure better understanding of the trajectory of language growth as well as optimize language outcomes by providing feedback in fine tuning the language intervention program. Objective To evaluate the receptive and expressive language in Hindi speaking children with up to 2 years of CI experience using revised receptive-expressive emergent language test-3ed. (REELT-3) at 6 months intervals and to compare it with that of children with normal hearing (NH). Methods The present study included 192 children divided in 2 groups, 96 children with CI (15.8 ± 6.7 months), and 96 age-matched children with NH (22.3 ± 7.9 months). A cross-sectional, prospective study design was used to measure the language ability score (LAS) at an interval of 6 months from the time of implantation (TIA), which is 0 to 6 months, 7 to 12 months, 13 to 18 months, and 19 to 24 months of CI usage. Results The two-way analysis of variance revealed that the LAS after 18 months of CI usage was similar to (F (3, 92) = 8.63, p= 0.19, ηp2 = 0.028) that of the children with NH. However, other demographic factors, for instance, gender (F (3, 92) = 1.73, p= 0.505, ηp2 = 0.002), parent's education, (F (3, 92) = 2.05, p= 0.937, ηp2 = 0.031), and financial background (F (3, 92) = 2.49, p= 0.351, ηp2 = 0.076) had no major impact on language. Conclusion Eighteen months of CI usage duration can potentially stimulate receptive and expressive language up to age-matched children with NH. A protocol of periodic assessment of language, at least of 6 months, may be developed to optimize language outcomes.

REM sleep and its Loss-Associated Epigenetic Regulation with Reference to Noradrenaline in Particular.

Sleep, an essential physiological process, has been divided into rapid eye movement sleep (REMS) and non-REMS (NREMS) in higher animals. REMS is a unique phenomenon that unlike other sleep-waking states is not under voluntary control. Directly or indirectly it influences or gets influenced by most of the physiological processes controlled by the brain. It has been proposed that REMS serves house-keeping function of the brain. Extensive research has shown that during REMS at least noradrenaline (NA)-ergic neurons must cease activity and upon REMS loss, there is increased level of NA in the brain, which then induces many of the REMS loss associated acute and chronic effects. The NA level is controlled by many bio-molecules, which are regulated at the molecular and transcriptional levels. Similarly, NA may also directly or indirectly modulate synthesis and levels of many molecules, which in turn may affect physiological processes. The burgeoning field of behavioral neuro-epigenetics has gained importance in recent years and explains the regulatory mechanisms underlying several behavioral phenomena. As REMS and its loss associated changes in NA modulates several pathophysiological processes, in this review we have attempted to explain on one hand how the epigenetic mechanisms regulating the gene expression of factors like tyrosine hydroxylase (TH), monoamine oxidase (MAO), noradrenaline transporter (NAT) control NA levels and on the other hand, how NA per se may affect other molecules in neural circuitry at epigenetic level resulting in behavioral changes in health and diseases. An understanding of these events will expose the molecular basis of REMS and its loss-associated pathophysiological changes; which are presented as testable hypothesis for confirmation.

Noradrenaline from Locus Coeruleus Neurons Acts on Pedunculo-Pontine Neurons to Prevent REM Sleep and Induces Its Loss-Associated Effects in Rats.

Normally, rapid eye movement sleep (REMS) does not appear during waking or non-REMS. Isolated, independent studies showed that elevated noradrenaline (NA) levels inhibit REMS and induce REMS loss-associated cytomolecular, cytomorphological, psychosomatic changes and associated symptoms. However, the source of NA and its target in the brain for REMS regulation and function in health and diseases remained to be confirmed in vivo. Using tyrosine hydroxylase (TH)-siRNA and virus-coated TH-shRNA in normal freely moving rats, we downregulated NA synthesis in locus coeruleus (LC) REM-OFF neurons in vivo. These TH-downregulated rats showed increased REMS, which was prevented by infusing NA into the pedunculo-pontine tegmentum (PPT), the site of REM-ON neurons, normal REMS returned after recovery. Moreover, unlike normal or control-siRNA- or shRNA-injected rats, upon REMS deprivation (REMSD) TH-downregulated rat brains did not show elevated Na-K ATPase (molecular changes) expression and activity. To the best of our knowledge, these are the first in vivo findings in an animal model confirming that NA from the LC REM-OFF neurons (1) acts on the PPT REM-ON neurons to prevent appearance of REMS, and (2) are responsible for inducing REMSD-associated molecular changes and symptoms. These observations clearly show neuro-physio-chemical mechanism of why normally REMS does not appear during waking. Also, that LC neurons are the primary source of NA, which in turn causes some, if not many, REMSD-associated symptoms and behavioral changes. The findings are proof-of-principle for the first time and hold potential to be exploited for confirmation toward treating REMS disorder and amelioration of REMS loss-associated symptoms in patients.

REM sleep loss associated changes in orexin-A levels in discrete brain areas in rats.

Rapid eye movement sleep (REMS) serves house-keeping function of the brain and its loss affects several pathophysiological processes. Relative levels of neurotransmitters including orexin A (Orx-A) in various parts of the brain in health and diseases are among the key factors for modulation of behaviors, including REMS. The level of neurotransmitter in an area in the brain directly depends on number of projecting neurons and their firing rates. The locus coeruleus (LC), the site of REM-OFF neurons, receives densest, while the pedunculo-pontine area (PPT), the site of REM-ON neurons receives lesser projections from the Orx-ergic neurons. Further, the Orx-ergic neurons are active during waking and silent during REMS and NREMS. Therefore, the level of Orx-A in discrete regions of the brain is likely to be different during normal and altered states, which in turn is likely to be responsible for altered behaviors in health and diseases, including in relation to REMS. Therefore, in the present study, we estimated Orx-A level in LC, cortex, posterior hypothalamus (PH), hippocampus, and PPT after 96 h REMSD, in post-deprivation recovered rats and in control rats. This is the first report of estimation of Orx-A in different brain regions after prolonged REMSD. It was observed that after REMSD the Orx-A level increased significantly in LC, cortex and PH which returned to normal level after recovery; however, the level did not change in the hippocampus and PPT. The Orx-A induced modulation of REMS could be secondary to increased waking.