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Hanley N, Paulissen J, Eastwood BJ, Gilmour G, Loomis S, Wafford KA, McCarthy A. Pharmacological Modulation of Sleep Homeostasis in Rat: Novel Effects of an mGluR2/3 Antagonist. Sleep 2020; 42:5491801. [PMID: 31106825 DOI: 10.1093/sleep/zsz123] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 04/25/2019] [Indexed: 12/19/2022] Open
Abstract
Increasing vigilance without incurring the negative consequences of extended wakefulness such as daytime sleepiness and cognitive impairment is a major challenge in treating many sleep disorders. The present work compares two closely related mGluR2/3 antagonists LY3020371 and LY341495 with two well-known wake-promoting compounds caffeine and d-amphetamine. Sleep homeostasis properties were explored in male Wistar rats by manipulating levels of wakefulness via (1) physiological sleep restriction (SR), (2) pharmacological action, or (3) a combination of these. A two-phase nonlinear mixed-effects model combining a quadratic and exponential function at an empirically estimated join point allowed the quantification of wake-promoting properties and any subsequent sleep rebound. A simple response latency task (SRLT) following SR assessed functional capacity of sleep-restricted animals treated with our test compounds. Caffeine and d-amphetamine increased wakefulness with a subsequent full recovery of non-rapid eye movement (NREM) and rapid eye movement (REM) sleep and were unable to fully reverse SR-induced impairments in SRLT. In contrast, LY3020371 increased wakefulness with no subsequent elevation of NREM sleep, delta power, delta energy, or sleep bout length and count, yet REM sleep recovered above baseline levels. Prior sleep pressure obtained using an SR protocol had no impact on the wake-promoting effect of LY3020371 and NREM sleep rebound remained blocked. Furthermore, LY341495 increased functional capacity across SRLT measures following SR. These results establish the critical role of glutamate in sleep homeostasis and support the existence of independent mechanisms for NREM and REM sleep homeostasis.
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Affiliation(s)
- Nicola Hanley
- Lilly Research Laboratories, Eli Lilly and Company, Windlesham, Surrey, UK
| | - Jerome Paulissen
- Clinical Division, Syneos Health (previously INC Research/InVentiv Health), Ann Arbor, MI
| | - Brian J Eastwood
- Lilly Research Laboratories, Eli Lilly and Company, Windlesham, Surrey, UK
| | - Gary Gilmour
- Lilly Research Laboratories, Eli Lilly and Company, Windlesham, Surrey, UK
| | - Sally Loomis
- Lilly Research Laboratories, Eli Lilly and Company, Windlesham, Surrey, UK
| | - Keith A Wafford
- Lilly Research Laboratories, Eli Lilly and Company, Windlesham, Surrey, UK
| | - Andrew McCarthy
- Lilly Research Laboratories, Eli Lilly and Company, Windlesham, Surrey, UK
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Pace M, Colombi I, Falappa M, Freschi A, Bandarabadi M, Armirotti A, Encarnación BM, Adamantidis AR, Amici R, Cerri M, Chiappalone M, Tucci V. Loss of Snord116 alters cortical neuronal activity in mice: a preclinical investigation of Prader–Willi syndrome. Hum Mol Genet 2020; 29:2051-2064. [DOI: 10.1093/hmg/ddaa084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 04/26/2020] [Accepted: 04/27/2020] [Indexed: 12/27/2022] Open
Abstract
Abstract
Prader–Willi syndrome (PWS) is a neurodevelopmental disorder that is characterized by metabolic alteration and sleep abnormalities mostly related to rapid eye movement (REM) sleep disturbances. The disease is caused by genomic imprinting defects that are inherited through the paternal line. Among the genes located in the PWS region on chromosome 15 (15q11-q13), small nucleolar RNA 116 (Snord116) has been previously associated with intrusions of REM sleep into wakefulness in humans and mice. Here, we further explore sleep regulation of PWS by reporting a study with PWScrm+/p− mouse line, which carries a paternal deletion of Snord116. We focused our study on both macrostructural electrophysiological components of sleep, distributed among REMs and nonrapid eye movements. Of note, here, we study a novel electroencephalography (EEG) graphoelements of sleep for mouse studies, the well-known spindles. EEG biomarkers are often linked to the functional properties of cortical neurons and can be instrumental in translational studies. Thus, to better understand specific properties, we isolated and characterized the intrinsic activity of cortical neurons using in vitro microelectrode array. Our results confirm that the loss of Snord116 gene in mice influences specific properties of REM sleep, such as theta rhythms and, for the first time, the organization of REM episodes throughout sleep–wake cycles. Moreover, the analysis of sleep spindles present novel specific phenotype in PWS mice, indicating that a new catalog of sleep biomarkers can be informative in preclinical studies of PWS.
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Affiliation(s)
- Marta Pace
- Genetics and Epigenetics of Behaviour (GEB), Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
| | - Ilaria Colombi
- Genetics and Epigenetics of Behaviour (GEB), Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
- Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università degli Studi di Genova, Genova 16132, Italy
| | - Matteo Falappa
- Genetics and Epigenetics of Behaviour (GEB), Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
- Dipartimento di Neuroscienze, Riabilitazione, Oftalmologia, Genetica e Scienze Materno-Infantili (DINOGMI), Università degli Studi di Genova, Genova 16132, Italy
| | - Andrea Freschi
- Genetics and Epigenetics of Behaviour (GEB), Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
| | - Mojtaba Bandarabadi
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, Bern 3010, Switzerland
| | - Andrea Armirotti
- Analytical Chemistry Facility, Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
| | | | - Antoine R Adamantidis
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, Bern 3010, Switzerland
- Department of Clinical Research, Inselspital University Hospital, University of Bern, Bern 3010, Switzerland
| | - Roberto Amici
- Department of Biomedical and NeuroMotor Sciences, Alma Mater Studiorum—University of Bologna, Bologna 40126, Italy
| | - Matteo Cerri
- Department of Biomedical and NeuroMotor Sciences, Alma Mater Studiorum—University of Bologna, Bologna 40126, Italy
| | - Michela Chiappalone
- Rehab Technologies, Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
| | - Valter Tucci
- Genetics and Epigenetics of Behaviour (GEB), Istituto Italiano di Tecnologia (IIT), Genova 16163, Italy
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Bjorness TE, Booth V, Poe GR. Hippocampal theta power pressure builds over non-REM sleep and dissipates within REM sleep episodes. Arch Ital Biol 2019; 156:112-126. [PMID: 30324607 DOI: 10.12871/00039829201833] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The theta rhythm during waking has been associated with voluntary motor activity and learning processes involving the hippocampus. Theta also occurs continuously during rapid eye movement (REM) sleep where it likely serves memory consolidation. Theta amplitude builds across wakefulness and is the best indicator of the homeostatic need for non-REM (NREM) sleep. Although REM sleep is homeostatically regulated independently of NREM sleep, the drivers of REM sleep regulation are under debate. The dynamics of theta within REM sleep bouts have not been thoroughly explored. We equipped 20 male rats with sleep instrumentation and hippocampal electrodes to measure theta across normal sleep/waking periods over the first 4 h of the sleep phase on two consecutive days. We found that theta power decreased by a third, on average, within individual REM sleep bouts, but recovered between bouts. Thus, there was no general decline in theta power across the duration of the recording period or between days. The time constant of theta power decline within a REM sleep bout was the same whether the bout was short, midlength, or long, and did not predict the behavioral state immediately following the REM sleep bout. Interestingly, the more time spent in NREM sleep prior to REM sleep, the larger the decline in theta power during REM sleep, indicating that REM sleep theta may be homeostatically driven by NREM sleep just as NREM delta power is driven by the length of prior waking and by waking theta. Potential causes and implications for this phenomenon are discussed.
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Affiliation(s)
| | | | - G R Poe
- Department of Integrative Biology and Physiology, 610 Charles E Young Drive East, Los Angeles, CA 90095, USA -
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Luppi M, Al-Jahmany AA, Del Vecchio F, Cerri M, Di Cristoforo A, Hitrec T, Martelli D, Perez E, Zamboni G, Amici R. Wake-sleep and cardiovascular regulatory changes in rats made obese by a high-fat diet. Behav Brain Res 2017; 320:347-355. [PMID: 28011172 DOI: 10.1016/j.bbr.2016.12.024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 12/15/2016] [Accepted: 12/19/2016] [Indexed: 11/18/2022]
Abstract
Obesity is known to be associated with alterations in wake-sleep (WS) architecture and cardiovascular parameters. This study was aimed at assessing the possible influence of diet-induced obesity (DIO) on sleep homeostasis and on the WS state-dependent levels of arterial pressure (AP) and heart rate in the rat. Two groups of age-matched Sprague-Dawley rats were fed either a high-fat hypercaloric diet, leading to DIO, or a normocaloric standard diet (lean controls) for 8 weeks. While under general anesthesia, animals were implanted with instrumentation for the recording of electroencephalogram, electromyogram, arterial pressure, and deep brain temperature. The experimental protocol consisted of 48h of baseline, 12h of gentle handling, enhancing wake and depressing sleep, and 36-h post-handling recovery. Compared to lean controls, DIO rats showed: i) the same amount of rapid-eye movement (REM) and non-REM (NREM) sleep in the rest period, although the latter was characterized by more fragmented episodes; ii) an increase in both REM sleep and NREM sleep in the activity period; iii) a comparable post-handling sleep homeostatic response, in terms of either the degree of Delta power increase during NREM sleep or the quantitative compensation of the REM sleep loss at the end of the 36-h recovery period; iv) significantly higher levels of AP, irrespectively of the different WS states and of the changes in their intensity throughout the experimental protocol. Overall, these changes may be the reflection of a modification in the activity of the hypothalamic areas where WS, autonomic, and metabolic regulations are known to interact.
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Affiliation(s)
- Marco Luppi
- Department of Biomedical and Neuromotor Sciences-Physiology, Alma Mater Studiorum - University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy.
| | - Abed A Al-Jahmany
- Department of Biomedical and Neuromotor Sciences-Physiology, Alma Mater Studiorum - University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy.
| | - Flavia Del Vecchio
- Department of Biomedical and Neuromotor Sciences-Physiology, Alma Mater Studiorum - University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy.
| | - Matteo Cerri
- Department of Biomedical and Neuromotor Sciences-Physiology, Alma Mater Studiorum - University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy.
| | - Alessia Di Cristoforo
- Department of Biomedical and Neuromotor Sciences-Physiology, Alma Mater Studiorum - University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy.
| | - Timna Hitrec
- Department of Biomedical and Neuromotor Sciences-Physiology, Alma Mater Studiorum - University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy.
| | - Davide Martelli
- Department of Biomedical and Neuromotor Sciences-Physiology, Alma Mater Studiorum - University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy; Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, 3052, Australia.
| | - Emanuele Perez
- Department of Biomedical and Neuromotor Sciences-Physiology, Alma Mater Studiorum - University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy.
| | - Giovanni Zamboni
- Department of Biomedical and Neuromotor Sciences-Physiology, Alma Mater Studiorum - University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy.
| | - Roberto Amici
- Department of Biomedical and Neuromotor Sciences-Physiology, Alma Mater Studiorum - University of Bologna, Piazza di Porta San Donato, 2, 40126, Bologna, Italy.
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Kostyalik D, Vas S, Kátai Z, Kitka T, Gyertyán I, Bagdy G, Tóthfalusi L. Chronic escitalopram treatment attenuated the accelerated rapid eye movement sleep transitions after selective rapid eye movement sleep deprivation: a model-based analysis using Markov chains. BMC Neurosci 2014; 15:120. [PMID: 25406958 PMCID: PMC4243313 DOI: 10.1186/s12868-014-0120-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 10/22/2014] [Indexed: 12/21/2022] Open
Abstract
Background Shortened rapid eye movement (REM) sleep latency and increased REM sleep amount are presumed biological markers of depression. These sleep alterations are also observable in several animal models of depression as well as during the rebound sleep after selective REM sleep deprivation (RD). Furthermore, REM sleep fragmentation is typically associated with stress procedures and anxiety. The selective serotonin reuptake inhibitor (SSRI) antidepressants reduce REM sleep time and increase REM latency after acute dosing in normal condition and even during REM rebound following RD. However, their therapeutic outcome evolves only after weeks of treatment, and the effects of chronic treatment in REM-deprived animals have not been studied yet. Results Chronic escitalopram- (10 mg/kg/day, osmotic minipump for 24 days) or vehicle-treated rats were subjected to a 3-day-long RD on day 21 using the flower pot procedure or kept in home cage. On day 24, fronto-parietal electroencephalogram, electromyogram and motility were recorded in the first 2 h of the passive phase. The observed sleep patterns were characterized applying standard sleep metrics, by modelling the transitions between sleep phases using Markov chains and by spectral analysis. Based on Markov chain analysis, chronic escitalopram treatment attenuated the REM sleep fragmentation [accelerated transition rates between REM and non-REM (NREM) stages, decreased REM sleep residence time between two transitions] during the rebound sleep. Additionally, the antidepressant avoided the frequent awakenings during the first 30 min of recovery period. The spectral analysis showed that the SSRI prevented the RD-caused elevation in theta (5–9 Hz) power during slow-wave sleep. Conversely, based on the aggregate sleep metrics, escitalopram had only moderate effects and it did not significantly attenuate the REM rebound after RD. Conclusion In conclusion, chronic SSRI treatment is capable of reducing several effects on sleep which might be the consequence of the sub-chronic stress caused by the flower pot method. These data might support the antidepressant activity of SSRIs, and may allude that investigating the rebound period following the flower pot protocol could be useful to detect antidepressant drug response. Markov analysis is a suitable method to study the sleep pattern.
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Affiliation(s)
- Diána Kostyalik
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary.
| | - Szilvia Vas
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary. .,MTA-SE, Neuropsychopharmacology and Neurochemistry Research Group, Budapest, Hungary.
| | - Zita Kátai
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary.
| | - Tamás Kitka
- Department of Neurophysiology, Gedeon Richter Plc., Gyömrői út 19-21, Budapest, Hungary.
| | - István Gyertyán
- Department of Behavioural Pharmacology, Gedeon Richter Plc., Gyömrői út 19-21, Budapest, Hungary.
| | - Gyorgy Bagdy
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary. .,MTA-SE, Neuropsychopharmacology and Neurochemistry Research Group, Budapest, Hungary.
| | - László Tóthfalusi
- Department of Pharmacodynamics, Semmelweis University, Budapest, Hungary.
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Waking and sleeping in the rat made obese through a high-fat hypercaloric diet. Behav Brain Res 2013; 258:145-52. [PMID: 24149066 DOI: 10.1016/j.bbr.2013.10.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/09/2013] [Accepted: 10/10/2013] [Indexed: 11/20/2022]
Abstract
Sleep restriction leads to metabolism dysregulation and to weight gain, which is apparently the consequence of an excessive caloric intake. On the other hand, obesity is associated with excessive daytime sleepiness in humans and promotes sleep in different rodent models of obesity. Since no consistent data on the wake-sleep (WS) pattern in diet-induced obesity rats are available, in the present study the effects on the WS cycle of the prolonged delivery of a high-fat hypercaloric (HC) diet leading to obesity were studied in Sprague-Dawley rats. The main findings are that animals kept under a HC diet for either four or eight weeks showed an overall decrease of time spent in wakefulness (Wake) and a clear Wake fragmentation when compared to animals kept under a normocaloric diet. The development of obesity was also accompanied with the occurrence of a larger daily amount of REM sleep (REMS). However, the capacity of HC animals to respond to a "Continuous darkness" exposure condition (obtained by extending the Dark period of the Light-Dark cycle to the following Light period) with an increase of Sequential REMS was dampened. The results of the present study indicate that if, on one hand, sleep curtailment promotes an excess of energy accumulation; on the other hand an over-exceeding energy accumulation depresses Wake. Thus, processes underlying energy homeostasis possibly interact with those underlying WS behavior, in order to optimize energy storage.
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Le Bon O. Which theories on sleep ultradian cycling are favored by the positive links found between the number of cycles and REMS? BIOL RHYTHM RES 2013. [DOI: 10.1080/09291016.2012.721590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Martelli D, Luppi M, Cerri M, Tupone D, Perez E, Zamboni G, Amici R. Waking and sleeping following water deprivation in the rat. PLoS One 2012; 7:e46116. [PMID: 23029406 PMCID: PMC3454381 DOI: 10.1371/journal.pone.0046116] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 08/28/2012] [Indexed: 11/30/2022] Open
Abstract
Wake-sleep (W-S) states are affected by thermoregulation. In particular, REM sleep (REMS) is reduced in homeotherms under a thermal load, due to an impairment of hypothalamic regulation of body temperature. The aim of this work was to assess whether osmoregulation, which is regulated at a hypothalamic level, but, unlike thermoregulation, is maintained across the different W-S states, could influence W-S occurrence. Sprague-Dawley rats, kept at an ambient temperature of 24°C and under a 12 h∶12 h light-dark cycle, were exposed to a prolonged osmotic challenge of three days of water deprivation (WD) and two days of recovery in which free access to water was restored. Two sets of parameters were determined in order to assess: i) the maintenance of osmotic homeostasis (water and food consumption; changes in body weight and fluid composition); ii) the effects of the osmotic challenge on behavioral states (hypothalamic temperature (Thy), motor activity, and W-S states). The first set of parameters changed in WD as expected and control levels were restored on the second day of recovery, with the exception of urinary Ca++ that almost disappeared in WD, and increased to a high level in recovery. As far as the second set is concerned, WD was characterized by the maintenance of the daily oscillation of Thy and by a decrease in activity during the dark periods. Changes in W-S states were small and mainly confined to the dark period: i) REMS slightly decreased at the end of WD and increased in recovery; ii) non-REM sleep (NREMS) increased in both WD and recovery, but EEG delta power, a sign of NREMS intensity, decreased in WD and increased in recovery. Our data suggest that osmoregulation interferes with the regulation of W-S states to a much lesser extent than thermoregulation.
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Affiliation(s)
- Davide Martelli
- Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
- Systems Neurophysiology Division, Florey Neuroscience Institutes, University of Melbourne, Melbourne, Australia
| | - Marco Luppi
- Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Matteo Cerri
- Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Domenico Tupone
- Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
- Oregon National Primate Research Center, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Emanuele Perez
- Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
| | - Giovanni Zamboni
- Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
- * E-mail:
| | - Roberto Amici
- Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna, Bologna, Italy
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DaSilva JK, Husain E, Lei Y, Mann GL, Tejani-Butt S, Morrison AR. Social partnering significantly reduced rapid eye movement sleep fragmentation in fear-conditioned, stress-sensitive Wistar-Kyoto rats. Neuroscience 2011; 199:193-204. [PMID: 22015926 DOI: 10.1016/j.neuroscience.2011.09.066] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 09/30/2011] [Accepted: 09/30/2011] [Indexed: 10/16/2022]
Abstract
Negative emotionality affects sleep-wake behavior in humans and rodents, and the Wistar-Kyoto (WKY) rat strain is known for its stress-sensitive phenotype. Analyzing rapid eye movement sleep (REMS) microarchitecture by separating REMS into single (siREMS; inter-REM episode interval>3 min) and sequential (seqREMS; interval≤3 min) episodes, we previously reported that cued fear conditioning (CFC) increased REMS fragmentation in WKY compared to Wistar rats by increasing the number of seqREMS episodes. Since social support affects fear responsiveness in humans, we hypothesized that social interaction with a naive partner would affect the sleep-wake response to CFC in WKY rats. Thus, male WKY rats were assigned to either the social support or the social isolation group. Animals were fear-conditioned to 10 tones (800 Hz, 90 dB, 5 s), each co-terminating with a mild foot shock (1.0 mA, 0.5 s), at 30-s intervals. All subjects underwent a tone-only test both 24 h (Day 1) and again two weeks (Day 14) later. Social partnering was achieved by providing the fear-conditioned rat with 30 min of interaction with its naive partner immediately after CFC and during the tone presentations on Day 1 and Day 14. The results indicate that while CFC increased freezing behavior in socially isolated WKY rats, it increased grooming behavior in socially partnered rats. Socially partnered rats had increased sleep efficiency during the light phase and spent less time in NREMS during the dark phase. The number of siREMS episodes increased during both the light and dark phases in partnered rats, and the number of seqREMS episodes increased in socially isolated rats. Our findings suggest that social partnering may protect WKY rats from the REMS fragmentation that is observed following CFC in isolation.
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Affiliation(s)
- J K DaSilva
- Department of Pharmaceutical Sciences, University of the Sciences in Philadelphia, 600 South 43rd Street, Philadelphia, PA 19104, USA.
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DaSilva JK, Lei Y, Madan V, Mann GL, Ross RJ, Tejani-Butt S, Morrison AR. Fear conditioning fragments REM sleep in stress-sensitive Wistar-Kyoto, but not Wistar, rats. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:67-73. [PMID: 20832443 PMCID: PMC3019280 DOI: 10.1016/j.pnpbp.2010.08.023] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 07/29/2010] [Accepted: 08/25/2010] [Indexed: 12/22/2022]
Abstract
Pavlovian conditioning is commonly used to investigate the mechanisms of fear learning. Because the Wistar-Kyoto (WKY) rat strain is particularly stress-sensitive, we investigated the effects of a psychological stressor on sleep in WKY compared to Wistar (WIS) rats. Male WKY and WIS rats were either fear-conditioned to tone cues or received electric foot shocks alone. In the fear-conditioning procedure, animals were exposed to 10 tones (800 Hz, 90 dB, 5s), each co-terminating with a foot shock (1.0 mA, 0.5s), at 30-s intervals. In the shock stress procedure, animals received 10 foot shocks at 30-s intervals, without tones. All subjects underwent a tone-only test both 24h (Day 1) and again two weeks (Day 14) later. Rapid eye movement sleep (REMS) continuity was investigated by partitioning REMS episodes into single (inter-REMS episode interval >3 min) and sequential (interval ≤ 3 min) episodes. In the fear-conditioned group, freezing increased from baseline in both strains, but the increase was maintained on Day 14 in WKY rats only. In fear-conditioned WKY rats, total REMS amount increased on Day 1, sequential REMS amount increased on Day 1 and Day 14, and single REMS amount decreased on Day 14. Alterations were due to changes in the number of sequential and single REMS episodes. Shock stress had no significant effect on REMS microarchitecture in either strain. The shift toward sequential REMS in fear-conditioned WKY rats may represent REMS fragmentation, and may provide a model for investigating the neurobiological mechanisms of sleep disturbances reported in posttraumatic stress disorder.
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Affiliation(s)
- Jamie K. DaSilva
- University of the Sciences in Philadelphia, Department of Pharmaceutical Sciences (Box 80), 600 South 43rd Street, Philadelphia, PA 19104, USA,Corresponding Author: Jamie K. DaSilva, Department of Pharmaceutical Sciences, University of the Sciences in Philadelphia, 600 South 43rd Street, Philadelphia, PA 19104,
| | - Yanlin Lei
- University of the Sciences in Philadelphia, Department of Pharmaceutical Sciences (Box 80), 600 South 43rd Street, Philadelphia, PA 19104, USA
| | - Vibha Madan
- University of Pennsylvania School of Veterinary Medicine, Department of Animal Biology, 3800 Spruce Street, Philadelphia, PA 19104, USA
| | - Graziella L. Mann
- University of Pennsylvania School of Veterinary Medicine, Department of Animal Biology, 3800 Spruce Street, Philadelphia, PA 19104, USA
| | - Richard J. Ross
- University of Pennsylvania School of Veterinary Medicine, Department of Animal Biology, 3800 Spruce Street, Philadelphia, PA 19104, USA,Philadelphia Veterans Affairs Medical Center, Behavioral Health Service, 3900 Woodland Avenue, Philadelphia, PA 19104, USA,University of Pennsylvania School of Medicine, Department of Psychiatry, 423 Guardian Drive, Philadelphia, PA 19104, USA
| | - Shanaz Tejani-Butt
- University of the Sciences in Philadelphia, Department of Pharmaceutical Sciences (Box 80), 600 South 43rd Street, Philadelphia, PA 19104, USA
| | - Adrian R. Morrison
- University of Pennsylvania School of Veterinary Medicine, Department of Animal Biology, 3800 Spruce Street, Philadelphia, PA 19104, USA
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Revel FG, Gottowik J, Gatti S, Wettstein JG, Moreau JL. Rodent models of insomnia: A review of experimental procedures that induce sleep disturbances. Neurosci Biobehav Rev 2009; 33:874-99. [DOI: 10.1016/j.neubiorev.2009.03.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Revised: 03/04/2009] [Accepted: 03/04/2009] [Indexed: 12/21/2022]
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Baracchi F, Zamboni G, Cerri M, Del Sindaco E, Dentico D, Jones CA, Luppi M, Perez E, Amici R. Cold exposure impairs dark-pulse capacity to induce REM sleep in the albino rat. J Sleep Res 2008; 17:166-79. [PMID: 18482105 DOI: 10.1111/j.1365-2869.2008.00658.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the albino rat, a REM sleep (REMS) onset can be induced with a high probability and a short latency when the light is suddenly turned off (dark pulse, DP) during non-REM sleep (NREMS). The aim of this study was to investigate to what extent DP delivery could overcome the integrative thermoregulatory mechanisms that depress REMS occurrence during exposure to low ambient temperature (Ta). To this aim, the efficiency of a non-rhythmical repetitive DP (3 min each) delivery during the first 6-h light period of a 12 h:12 h light-dark cycle in inducing REMS was studied in the rat, through the analysis of electroencephalogram, electrocardiogram, hypothalamic temperature and motor activity at different Tas. The results showed that DP delivery triggers a transition from NREMS to REMS comparable to that which occurs spontaneously. However, the efficiency of DP delivery in inducing REMS was reduced during cold exposure to an extent comparable with that observed in spontaneous REMS occurrence. Such impairment was associated with low Delta activity and high sympathetic tone when DPs were delivered. Repetitive DP administration increased REMS amount during the delivery period and a subsequent negative REMS rebound was observed. In conclusion, DP delivery did not overcome the integrative thermoregulatory mechanisms that depress REMS in the cold. These results underline the crucial physiological meaning of the mutual exclusion of thermoregulatory activation and REMS occurrence, and support the hypothesis that the suspension of the central control of body temperature is a prerequisite for REMS occurrence.
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Affiliation(s)
- Francesca Baracchi
- Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna, Italy
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Amici R, Cerri M, Ocampo-Garcés A, Baracchi F, Dentico D, Jones CA, Luppi M, Perez E, Parmeggiani PL, Zamboni G. Cold exposure and sleep in the rat: REM sleep homeostasis and body size. Sleep 2008; 31:708-15. [PMID: 18517040 DOI: 10.1093/sleep/31.5.708] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
STUDY OBJECTIVES Exposure to low ambient temperature (Ta) depresses REM sleep (REMS) occurrence. In this study, both short and long-term homeostatic aspects of REMS regulation were analyzed during cold exposure and during subsequent recovery at Ta 24 degrees C. DESIGN EEG activity, hypothalamic temperature, and motor activity were studied during a 24-h exposure to Tas ranging from 10 degrees C to -10 degrees C and for 4 days during recovery. SETTING Laboratory of Physiological Regulation during the Wake-Sleep Cycle, Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna. SUBJECTS 24 male albino rats. INTERVENTIONS Animals were implanted with electrodes for EEG recording and a thermistor to measure hypothalamic temperature. MEASUREMENTS AND RESULTS REMS occurrence decreased proportionally with cold exposure, but a fast compensatory REMS rebound occurred during the first day of recovery when the previous loss went beyond a "fast rebound" threshold corresponding to 22% of the daily REMS need. A slow REMS rebound apparently allowed the animals to fully restore the previous REMS loss during the following 3 days of recovery. CONCLUSION Comparing the present data on rats with data from earlier studies on cats and humans, it appears that small mammals have less tolerance for REMS loss than large ones. In small mammals, this low tolerance may be responsible on a short-term basis for the shorter wake-sleep cycle, and on long-term basis, for the higher percentage of REMS that is quickly recovered following REMS deprivation.
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Affiliation(s)
- Roberto Amici
- Department of Human and General Physiology, Alma Mater Studiorum-University of Bologna, Italy.
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Esposito MJ, Zamboni G, Natale V, Lucidi F, Devoto A, Violani C. Single and Sequential REM sleep episodes in humans: a phylogenetic left-over? Neurosci Lett 2004; 368:52-6. [PMID: 15342133 DOI: 10.1016/j.neulet.2004.06.057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2004] [Revised: 06/14/2004] [Accepted: 06/22/2004] [Indexed: 11/20/2022]
Abstract
The occurrence of REM sleep in the rat appears to be under the control of either sleep related processes and homeostatic regulation of physiological variables. With respect to this, it has been observed that in this species REM sleep may occur in the form of two types of episodes, Single and Sequential episodes, which are supposed to play a different functional role. Since it is possible to distinguish Single and Sequential REM sleep episodes also in human beings, the aim of this pilot study was to asses whether a sleep deprivation may differently affect these two types of REM episodes. The sleep deprivation was induced in young human subjects by a progressive restriction of sleep within the same night period. Seventy-two PSG tracing belonging to six subjects have been analyzed. The results show that sleep deprivation does not significantly affect the relative occurrence of Single and Sequential REM sleep episodes, suggesting that in human beings these two types of REM episodes might not have a different functional role.
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Affiliation(s)
- Maria José Esposito
- Department of Psychology, University of Bologna, viale Berti Pichat, 5, 40127 Bologna, Italy.
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Dewasmes G, Loos N, Delanaud S, Dewasmes D, Ramadan W. Pattern of rapid-eye movement sleep episode occurrence after an immobilization stress in the rat. Neurosci Lett 2004; 355:17-20. [PMID: 14729224 DOI: 10.1016/j.neulet.2003.10.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Rapid-eye movement sleep (REMS) in the rat occurs in the form of episodes separated by long (>3 min: isolated REMS episodes, IREMSEs) and short (<3 min: sequential REMS episodes, SREMSEs) intervals. The mechanism clustering SREMSEs is thought to be better suited to increase the amount of REMS when its drive is high. We tested this hypothesis in a new situation by transiently augmenting this drive with a moderate psychogenic stress. After a 90-min immobilization stress, REMS increased by 54% over the rest of the dark phase. This increase was associated with a modest increase in IREMSEs (+40%), but a massive increase in SREMSEs (+300%). Thus, the mechanism that clusters REMS episodes operates in response to a moderate psychogenic stress imposed in standard laboratory conditions and not preceded by sleep deprivation.
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Affiliation(s)
- G Dewasmes
- University of Picardie J. Verne, School of Medicine of Amiens, ETP-APC, 3 rue des Louvels, 80036 Amiens Cedex, France.
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Amici R, Sanford LD, Kearney K, McInerney B, Ross RJ, Horner RL, Morrison AR. A serotonergic (5-HT2) receptor mechanism in the laterodorsal tegmental nucleus participates in regulating the pattern of rapid-eye-movement sleep occurrence in the rat. Brain Res 2004; 996:9-18. [PMID: 14670626 DOI: 10.1016/j.brainres.2003.09.026] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Serotonin [5-hydroxytryptamine (5-HT)] plays an inhibitory role in rapid-eye-movement (REM) sleep although the exact mechanism(s) and site(s) of action are not known. It is commonly assumed that 5-HT exerts its influence on REM sleep via input from the dorsal raphe nucleus (DRN) directly onto cholinergic neurons involved in the generation of REM sleep. 5-HT(2) receptor sites have been found on cholinergic neurons in the laterodorsal tegmental nucleus (LDT) and pedunculopontine tegmental nucleus (PPT). We locally microinjected the 5-HT(2) agonist DOI ((+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl) and the 5-HT(2) antagonist, ketanserin, in LDT in rats to determine whether these receptor sites are involved in the regulation of behavioral states. DOI and ketanserin primarily affected REM sleep, by significantly decreasing or increasing, respectively, the number, but not the duration, of REM sleep episodes. DOI specifically decreased the occurrence of clusters of REM sleep episodes appearing at intervals less than or equal to 3 min (sequential episodes) without affecting single episodes separated by more than 3 min. An opposite effect of ketanserin on REM sleep clusters, although not statistically significant, was observed.
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Affiliation(s)
- Roberto Amici
- Department of Human and General Physiology, University of Bologna, Bologna, Italy
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Amici R, Morales-Cobas G, Jones CA, Perez E, Torterolo P, Zamboni G, Parmeggiani PL. REM sleep enhancement due to rhythmical auditory stimulation in the rat. Behav Brain Res 2001; 123:155-63. [PMID: 11399328 DOI: 10.1016/s0166-4328(01)00203-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
From a physiological viewpoint, REM sleep (REMS) is a period during which homeostatic physiological regulations are impaired. In the rat, REMS occurs in two forms respectively characterized by episodes separated by long intervals (single REMS episodes) and by episodes which have short intervals and occur in sequences (REMS clusters). Since the partition of REMS in the form of either single or clustered episodes may reveal how the REMS drive and body homeostatic processes interact in the control of REMS occurrence, we have used this approach to clarify the effects of the rhythmical delivery of an auditory stimulus (1000 Hz, 63 or 88 dB, 50 ms, every 20 s), which has been previously observed by different authors to enhance REMS in the absence of a previous sleep deprivation. Stimuli were delivered to pairs of animals and triggered by the occurrence of REMS in one rat (REMS-selective stimulation), whilst the other animal received the same stimulus irrespectively of the stage of the wake-sleep cycle (REMS-unselective stimulation). The results showed that the REMS-selective stimulation did not change the overall amount of REMS, since an increase in the occurrence of REMS clusters was concomitant with a decrease in the occurrence of single REMS episodes. In contrast, under the REMS-unselective stimulation, the total amount of REMS was increased during the second day of stimulation through an increase in the duration of both types of REMS episodes. Since during the REMS-unselective stimulation 87% of the stimuli fell outside REMS (i.e., during the REMS interval), the results show that the occurrence of REMS is more consistently affected when the stimuli are delivered in a period during which homeostatic physiological regulations are fully operant.
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Affiliation(s)
- R Amici
- Dipartimento di Fisiologia Umana e Generale, Università di Bologna, Piazza di Porta S. Donato 2, I-40127 Bologna, Italy.
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