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Yamaguchi T, Hamada T, Iijima N. Differences in recovery processes of circadian oscillators in various tissues after sevoflurane treatment in vivo. Biochem Biophys Rep 2022; 30:101258. [PMID: 35434385 PMCID: PMC9006766 DOI: 10.1016/j.bbrep.2022.101258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 03/23/2022] [Accepted: 04/01/2022] [Indexed: 11/30/2022] Open
Abstract
The inhalation anesthetic sevoflurane reversibly suppresses Period2 (Per2) mRNA expression in the suprachiasmatic nucleus (SCN). However, a discrepancy exists in phase shifting of the Per2 expression rhythm between sevoflurane application in rats (in vivo application) and explants (ex vivo application). This investigation aimed to resolve this issue. First, tissues from the SCN, choroid plexus in the lateral ventricle (CP-LV), and choroid plexus in the fourth ventricle (CP–4V), which are robust circadian oscillators, and pineal gland (PG) tissue, which is a circadian influencer, were prepared from Per2::dLuc transgenic rats. Significant phase responses of bioluminescence rhythms for different preparation times were monitored in the four tissue explant types. Second, tissue explants were prepared from anesthetized rats immediately after sevoflurane treatment, and bioluminescence rhythms were compared with those from non-anesthetized rats at various preparation times. Regarding bioluminescence rhythm phases, in vivo application of sevoflurane induced phase shifts in CP-LV, CP-4V, and PG explants according to the times that rats were administered anesthesia and the explants were prepared. Phase shifts in these peripheral explants were withdrawn due to the recovery period after the anesthetic treatment, which suggests that peripheral tissues require the assistance of related tissues or organs to correct phase shifts. In contrast, no phase shifts were observed in SCN explants. These results indicated that SCN explants can independently correct bioluminescence rhythm phase. The bioluminescence intensity of explants was also decreased after in vivo sevoflurane application. The suppressive effects on SCN explants were withdrawn due to a recovery day after the anesthetic treatment. In contrast, the suppressive effects on the bioluminescence intensities of CP-LV, CP-4V, and PG explants remained at 30 days after anesthesia administration. These results suggest that anesthetic suppression is imprinted within the peripheral tissues. We monitored bioluminescence in explants from Per2::dLuc rats after anesthesia. Sevoflurane induced phase shifts in peripheral explants but not in the SCN. Phase shifts in peripheral explants were withdrawn due to recovery period. Sevoflurane weakened the bioluminescence intensity of all explant types. The suppressive effects on peripheral explants were remained in a week later.
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Affiliation(s)
- Takeshi Yamaguchi
- Center for Basic Medical Research, International University of Health and Welfare, Ohtawara, Tochigi, Japan
| | - Toshiyuki Hamada
- Department of Pharmacology, International University of Health and Welfare, Ohtawara, Tochigi, Japan
| | - Norio Iijima
- Center for Basic Medical Research, International University of Health and Welfare, Ohtawara, Tochigi, Japan
- Corresponding author.
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Lee R, McGee A, Fernandez FX. Systematic review of drugs that modify the circadian system's phase-shifting responses to light exposure. Neuropsychopharmacology 2022; 47:866-879. [PMID: 34961774 PMCID: PMC8882192 DOI: 10.1038/s41386-021-01251-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 11/08/2021] [Accepted: 11/30/2021] [Indexed: 11/09/2022]
Abstract
We searched PubMed for primary research quantifying drug modification of light-induced circadian phase-shifting in rodents. This search, conducted for work published between 1960 and 2018, yielded a total of 146 papers reporting results from 901 studies. Relevant articles were those with any extractable data on phase resetting in wildtype (non-trait selected) rodents administered a drug, alongside a vehicle/control group, near or at the time of exposure. Most circadian pharmacology experiments were done using drugs thought to act directly on either the brain's central pacemaker, the suprachiasmatic nucleus (SCN), the SCN's primary relay, the retinohypothalamic tract, secondary pathways originating from the medial/dorsal raphe nuclei and intergeniculate leaflet, or the brain's sleep-arousal centers. While the neurotransmitter systems underlying these circuits were of particular interest, including those involving glutamate, gamma-aminobutyric acid, serotonin, and acetylcholine, other signaling modalities have also been assessed, including agonists and antagonists of receptors linked to dopamine, histamine, endocannabinoids, adenosine, opioids, and second-messenger pathways downstream of glutamate receptor activation. In an effort to identify drugs that unduly influence circadian responses to light, we quantified the net effects of each drug class by ratioing the size of the phase-shift observed after administration to that observed with vehicle in a given experiment. This allowed us to organize data across the literature, compare the relative efficacy of one mechanism versus another, and clarify which drugs might best suppress or potentiate phase resetting. Aggregation of the available data in this manner suggested that several candidates might be clinically relevant as auxiliary treatments to suppress ectopic light responses during shiftwork or amplify the circadian effects of timed bright light therapy. Future empirical research will be necessary to validate these possibilities.
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Affiliation(s)
- Robert Lee
- Department of Psychology, University of Arizona, Tucson, AZ, USA
| | - Austin McGee
- Department of Psychology, University of Arizona, Tucson, AZ, USA
| | - Fabian-Xosé Fernandez
- Department of Psychology, University of Arizona, Tucson, AZ, USA.
- Department of Neurology, University of Arizona, Tucson, AZ, USA.
- BIO5 and McKnight Brain Research Institutes, Tucson, AZ, USA.
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The Effects of General Anaesthesia and Light on Behavioural Rhythms and GABA A Receptor Subunit Expression in the Mouse SCN. Clocks Sleep 2021; 3:482-494. [PMID: 34563056 PMCID: PMC8482144 DOI: 10.3390/clockssleep3030034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/15/2021] [Accepted: 09/15/2021] [Indexed: 11/16/2022] Open
Abstract
General anaesthesia (GA) is known to affect the circadian clock. However, the mechanisms that underlie GA-induced shifting of the clock are less well understood. Activation of γ-aminobutyric acid (GABA)-type A receptors (GABAAR) in the suprachiasmatic nucleus (SCN) can phase shift the clock and thus GABA and its receptors represent a putative pathway via which GA exerts its effect on the clock. Here, we investigated the concurrent effects of the inhalational anaesthetic, isoflurane, and light, on mouse behavioural locomotor rhythms and on α1, β3, and γ2 GABAAR subunit expression in the SCN of the mouse brain. Behavioural phase shifts elicited by exposure of mice to four hours of GA (2% isoflurane) and light (400 lux) (n = 60) were determined by recording running wheel activity rhythms in constant conditions (DD). Full phase response curves for the effects of GA + light on behavioural rhythms show that phase shifts persist in anaesthetized mice exposed to light. Daily variation was detected in all three GABAAR subunits in LD 12:12. The γ2 subunit expression was significantly increased following GA in DD (compared to light alone) at times of large behavioural phase delays. We conclude that the phase shifting effect of light on the mouse clock is not blocked by GA administration, and that γ2 may potentially be involved in the phase shifting effect of GA on the clock. Further analysis of GABAAR subunit expression in the SCN will be necessary to confirm its role.
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Ludin NM, Orts-Sebastian A, Cheeseman JF, Chong J, Merry AF, Cumin D, Yamazaki S, Pawley MDM, Warman GR. General Anaesthesia Shifts the Murine Circadian Clock in a Time-Dependant Fashion. Clocks Sleep 2021; 3:87-97. [PMID: 33530488 PMCID: PMC7930986 DOI: 10.3390/clockssleep3010006] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/13/2021] [Accepted: 01/20/2021] [Indexed: 01/23/2023] Open
Abstract
Following general anaesthesia (GA), patients frequently experience sleep disruption and fatigue, which has been hypothesized to result at least in part by GA affecting the circadian clock. Here, we provide the first comprehensive time-dependent analysis of the effects of the commonly administered inhalational anaesthetic, isoflurane, on the murine circadian clock, by analysing its effects on (a) behavioural locomotor rhythms and (b) PER2::LUC expression in the suprachiasmatic nuclei (SCN) of the mouse brain. Behavioural phase shifts elicited by exposure of mice (n = 80) to six hours of GA (2% isoflurane) were determined by recording wheel-running rhythms in constant conditions (DD). Phase shifts in PER2::LUC expression were determined by recording bioluminescence in organotypic SCN slices (n = 38) prior to and following GA exposure (2% isoflurane). Full phase response curves for the effects of GA on behaviour and PER2::LUC rhythms were constructed, which show that the effects of GA are highly time-dependent. Shifts in SCN PER2 expression were much larger than those of behaviour (c. 0.7 h behaviour vs. 7.5 h PER2::LUC). We discuss the implications of this work for understanding how GA affects the clock, and how it may inform the development of chronotherapeutic strategies to reduce GA-induced phase-shifting in patients.
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Affiliation(s)
- Nicola M. Ludin
- Department of Anaesthesiology, School of Medicine, University of Auckland, 1142 Auckland, New Zealand; (N.M.L.); (A.O.-S.); (J.F.C.); (J.C.); (A.F.M.); (D.C.); (M.D.M.P.)
| | - Alma Orts-Sebastian
- Department of Anaesthesiology, School of Medicine, University of Auckland, 1142 Auckland, New Zealand; (N.M.L.); (A.O.-S.); (J.F.C.); (J.C.); (A.F.M.); (D.C.); (M.D.M.P.)
| | - James F. Cheeseman
- Department of Anaesthesiology, School of Medicine, University of Auckland, 1142 Auckland, New Zealand; (N.M.L.); (A.O.-S.); (J.F.C.); (J.C.); (A.F.M.); (D.C.); (M.D.M.P.)
| | - Janelle Chong
- Department of Anaesthesiology, School of Medicine, University of Auckland, 1142 Auckland, New Zealand; (N.M.L.); (A.O.-S.); (J.F.C.); (J.C.); (A.F.M.); (D.C.); (M.D.M.P.)
| | - Alan F. Merry
- Department of Anaesthesiology, School of Medicine, University of Auckland, 1142 Auckland, New Zealand; (N.M.L.); (A.O.-S.); (J.F.C.); (J.C.); (A.F.M.); (D.C.); (M.D.M.P.)
| | - David Cumin
- Department of Anaesthesiology, School of Medicine, University of Auckland, 1142 Auckland, New Zealand; (N.M.L.); (A.O.-S.); (J.F.C.); (J.C.); (A.F.M.); (D.C.); (M.D.M.P.)
| | - Shin Yamazaki
- Department of Neuroscience, Peter O’Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA;
| | - Matthew D. M. Pawley
- Department of Anaesthesiology, School of Medicine, University of Auckland, 1142 Auckland, New Zealand; (N.M.L.); (A.O.-S.); (J.F.C.); (J.C.); (A.F.M.); (D.C.); (M.D.M.P.)
- School of Natural and Computational Sciences, Massey University, 0745 Auckland, New Zealand
| | - Guy R. Warman
- Department of Anaesthesiology, School of Medicine, University of Auckland, 1142 Auckland, New Zealand; (N.M.L.); (A.O.-S.); (J.F.C.); (J.C.); (A.F.M.); (D.C.); (M.D.M.P.)
- Correspondence: ; Tel.: +64-9-9239302
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Jha PK, Bouâouda H, Kalsbeek A, Challet E. Distinct feedback actions of behavioural arousal to the master circadian clock in nocturnal and diurnal mammals. Neurosci Biobehav Rev 2021; 123:48-60. [PMID: 33440199 DOI: 10.1016/j.neubiorev.2020.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 09/16/2020] [Accepted: 12/10/2020] [Indexed: 12/20/2022]
Abstract
The master clock in the suprachiasmatic nucleus (SCN) of the hypothalamus provides a temporal pattern of sleep and wake that - like many other behavioural and physiological rhythms - is oppositely phased in nocturnal and diurnal animals. The SCN primarily uses environmental light, perceived through the retina, to synchronize its endogenous circadian rhythms with the exact 24 h light/dark cycle of the outside world. The light responsiveness of the SCN is maximal during the night in both nocturnal and diurnal species. Behavioural arousal during the resting period not only perturbs sleep homeostasis, but also acts as a potent non-photic synchronizing cue. The feedback action of arousal on the SCN is mediated by processes involving several brain nuclei and neurotransmitters, which ultimately change the molecular functions of SCN pacemaker cells. Arousing stimuli during the sleeping period differentially affect the circadian system of nocturnal and diurnal species, as evidenced by the different circadian windows of sensitivity to behavioural arousal. In addition, arousing stimuli reduce and increase light resetting in nocturnal and diurnal species, respectively. It is important to address further question of circadian impairments associated with shift work and trans-meridian travel not only in the standard nocturnal laboratory animals but also in diurnal animal models.
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Affiliation(s)
- Pawan Kumar Jha
- Circadian Clocks and Metabolism Team, Institute of Cellular and Integrative Neurosciences, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, France; Department of Endocrinology and Metabolism, Amsterdam University Medical Center (AUMC), University of Amsterdam, the Netherlands; Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, the Netherlands.
| | - Hanan Bouâouda
- Circadian Clocks and Metabolism Team, Institute of Cellular and Integrative Neurosciences, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, France
| | - Andries Kalsbeek
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center (AUMC), University of Amsterdam, the Netherlands; Hypothalamic Integration Mechanisms, Netherlands Institute for Neuroscience, Amsterdam, the Netherlands
| | - Etienne Challet
- Circadian Clocks and Metabolism Team, Institute of Cellular and Integrative Neurosciences, Centre National de la Recherche Scientifique (CNRS), University of Strasbourg, France
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Gile J, Oyama Y, Shuff S, Eckle T. A Role for the Adenosine ADORA2B Receptor in Midazolam Induced Cognitive Dysfunction. Curr Pharm Des 2020; 26:4330-4337. [PMID: 32294028 DOI: 10.2174/1381612826666200415171622] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 04/01/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND We recently reported a role for the circadian rhythm protein Period 2 (PER2) in midazolam induced cognitive dysfunction. Based on previous studies showing a critical role for the adenosine A2B receptor (ADORA2B) in PER2 regulation, we hypothesized that hippocampal ADORA2B is crucial for cognitive function. METHODS Midazolam treated C57BL/6J mice were analyzed for Adora2b hippocampal mRNA expression levels, and spontaneous T-maze alternation was determined in Adora2b-/- mice. Using the specific ADORA2B agonist BAY-60-6583 in midazolam treated C57BL/6J mice, we analyzed hippocampal Per2 mRNA expression levels and spontaneous T-maze alternation. Finally, Adora2b-/- mice were assessed for mRNA expression of markers for inflammation or cognitive function in the hippocampus. RESULTS Midazolam treatment significantly downregulated Adora2b or Per2 mRNA in the hippocampus of C57BL/6J mice, and hippocampal PER2 protein expression or T-maze alternation was significantly reduced in Adora2b-/- mice. ADORA2B agonist BAY-60-6583 restored midazolam mediated reduction in spontaneous alternation in C57BL/6J mice. Analysis of hippocampal Tnf-α or Il-6 mRNA levels in Adora2b-/- mice did not reveal an inflammatory phenotype. However, C-fos, a critical component of hippocampus-dependent learning and memory, was significantly downregulated in the hippocampus of Adora2b-/- mice. CONCLUSION These results suggest a role of ADORA2B in midazolam induced cognitive dysfunction. Further, our data demonstrate that BAY-60-6583 treatment restores midazolam induced cognitive dysfunction, possibly via increases of Per2. Additional mechanistic studies hint towards C-FOS as another potential underlying mechanism of memory impairment in Adora2b-/- mice. These findings suggest the ADORA2B agonist as a potential therapy in patients with midazolam induced cognitive dysfunction.
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Affiliation(s)
- Jennifer Gile
- Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Yoshimasa Oyama
- Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Sydney Shuff
- Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO 80045, United States
| | - Tobias Eckle
- Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO 80045, United States
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Harvey JRM, Plante AE, Meredith AL. Ion Channels Controlling Circadian Rhythms in Suprachiasmatic Nucleus Excitability. Physiol Rev 2020; 100:1415-1454. [PMID: 32163720 DOI: 10.1152/physrev.00027.2019] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Animals synchronize to the environmental day-night cycle by means of an internal circadian clock in the brain. In mammals, this timekeeping mechanism is housed in the suprachiasmatic nucleus (SCN) of the hypothalamus and is entrained by light input from the retina. One output of the SCN is a neural code for circadian time, which arises from the collective activity of neurons within the SCN circuit and comprises two fundamental components: 1) periodic alterations in the spontaneous excitability of individual neurons that result in higher firing rates during the day and lower firing rates at night, and 2) synchronization of these cellular oscillations throughout the SCN. In this review, we summarize current evidence for the identity of ion channels in SCN neurons and the mechanisms by which they set the rhythmic parameters of the time code. During the day, voltage-dependent and independent Na+ and Ca2+ currents, as well as several K+ currents, contribute to increased membrane excitability and therefore higher firing frequency. At night, an increase in different K+ currents, including Ca2+-activated BK currents, contribute to membrane hyperpolarization and decreased firing. Layered on top of these intrinsically regulated changes in membrane excitability, more than a dozen neuromodulators influence action potential activity and rhythmicity in SCN neurons, facilitating both synchronization and plasticity of the neural code.
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Affiliation(s)
- Jenna R M Harvey
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Amber E Plante
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Andrea L Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
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9
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Ben-Hamouda N, Poirel VJ, Dispersyn G, Pévet P, Challet E, Pain L. Short-term propofol anaesthesia down-regulates clock genes expression in the master clock. Chronobiol Int 2018; 35:1735-1741. [DOI: 10.1080/07420528.2018.1499107] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Nawfel Ben-Hamouda
- Institut des neurosciences cellulaires et integratives, Neurobiology of Rhythms, CNRS (UPR3212), Université de Strasbourg, Strasbourg, France
- Adult intensive Care Medicine and Burns, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Vincent-Joseph Poirel
- Institut des neurosciences cellulaires et integratives, Neurobiology of Rhythms, CNRS (UPR3212), Université de Strasbourg, Strasbourg, France
| | - Garance Dispersyn
- Institut des neurosciences cellulaires et integratives, Neurobiology of Rhythms, CNRS (UPR3212), Université de Strasbourg, Strasbourg, France
- Institut de recherche biomedicale des armees, Bretigny-sur-Orge, France
| | - Paul Pévet
- Institut des neurosciences cellulaires et integratives, Neurobiology of Rhythms, CNRS (UPR3212), Université de Strasbourg, Strasbourg, France
| | - Etienne Challet
- Institut des neurosciences cellulaires et integratives, Neurobiology of Rhythms, CNRS (UPR3212), Université de Strasbourg, Strasbourg, France
| | - Laure Pain
- Institut des neurosciences cellulaires et integratives, Neurobiology of Rhythms, CNRS (UPR3212), Université de Strasbourg, Strasbourg, France
- Anesthesiology, Hopitaux universitaires de Strasbourg, Strasbourg, France
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Kim M, de la Peña JB, Cheong JH, Kim HJ. Neurobiological Functions of the Period Circadian Clock 2 Gene, Per2. Biomol Ther (Seoul) 2018; 26:358-367. [PMID: 29223143 PMCID: PMC6029676 DOI: 10.4062/biomolther.2017.131] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/10/2017] [Accepted: 08/22/2017] [Indexed: 12/14/2022] Open
Abstract
Most organisms have adapted to a circadian rhythm that follows a roughly 24-hour cycle, which is modulated by both internal (clock-related genes) and external (environment) factors. In such organisms, the central nervous system (CNS) is influenced by the circadian rhythm of individual cells. Furthermore, the period circadian clock 2 (Per2) gene is an important component of the circadian clock, which modulates the circadian rhythm. Per2 is mainly expressed in the suprachiasmatic nucleus (SCN) of the hypothalamus as well as other brain areas, including the midbrain and forebrain. This indicates that Per2 may affect various neurobiological activities such as sleeping, depression, and addiction. In this review, we focus on the neurobiological functions of Per2, which could help to better understand its roles in the CNS.
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Affiliation(s)
- Mikyung Kim
- Department of Pharmacy, Uimyung Research Institute for Neuroscience, Sahmyook University, Seoul 01795, Republic of Korea
| | - June Bryan de la Peña
- Department of Pharmacy, Uimyung Research Institute for Neuroscience, Sahmyook University, Seoul 01795, Republic of Korea
| | - Jae Hoon Cheong
- Department of Pharmacy, Uimyung Research Institute for Neuroscience, Sahmyook University, Seoul 01795, Republic of Korea
| | - Hee Jin Kim
- Department of Pharmacy, Uimyung Research Institute for Neuroscience, Sahmyook University, Seoul 01795, Republic of Korea
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Temporal Regulation of GABA A Receptor Subunit Expression: Role in Synaptic and Extrasynaptic Communication in the Suprachiasmatic Nucleus. eNeuro 2017; 4:eN-NWR-0352-16. [PMID: 28466071 PMCID: PMC5411165 DOI: 10.1523/eneuro.0352-16.2017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 04/11/2017] [Accepted: 04/12/2017] [Indexed: 11/21/2022] Open
Abstract
Recent molecular studies suggest that the expression levels of δ and γ2 GABAA receptor (GABAAR) subunits regulate the balance between synaptic and extrasynaptic GABA neurotransmission in multiple brain regions. We investigated the expression of GABAAδ and GABAAγ2 and the functional significance of a change in balance between these subunits in a robust local GABA network contained within the suprachiasmatic nucleus of the hypothalamus (SCN). Muscimol, which can activate both synaptic and extrasynaptic GABAARs, injected into the SCN during the day phase advanced the circadian pacemaker, whereas injection of the extrasynaptic GABAA superagonist 4,5,6,7-tetrahydroisoxazolo(5,4-c)pyridin-3-ol (THIP) had no effect on circadian phase. In contrast, injection of either THIP or muscimol during the night was sufficient to block the phase shifting effects of light. Gene expression analysis of the whole SCN revealed different temporal patterns in GABAAδ and GABAAγ2 mRNA expression. When examined across all subregions of the SCN, quantitative immunohistochemical analysis found no significant variations in GABAAδ protein immunoreactivity (IR) but did find significant variations in GABAAγ2 protein-IR in hamsters housed in either LD cycles or in constant darkness. Remarkably, significant interactions in the ratio of GABAAδ:GABAAγ2 subunits between lighting condition and circadian phase occurred only within one highly discrete anatomical area of the SCN; a region that functions as the input for lighting information from the retina. Taken together, these data support the hypothesis that the balance between synaptic and extrasynaptic GABAARs determines the functional response to GABA, and that this balance is differentially regulated in a region-specific manner.
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12
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Albers HE, Walton JC, Gamble KL, McNeill JK, Hummer DL. The dynamics of GABA signaling: Revelations from the circadian pacemaker in the suprachiasmatic nucleus. Front Neuroendocrinol 2017; 44:35-82. [PMID: 27894927 PMCID: PMC5225159 DOI: 10.1016/j.yfrne.2016.11.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 10/16/2016] [Accepted: 11/22/2016] [Indexed: 12/31/2022]
Abstract
Virtually every neuron within the suprachiasmatic nucleus (SCN) communicates via GABAergic signaling. The extracellular levels of GABA within the SCN are determined by a complex interaction of synthesis and transport, as well as synaptic and non-synaptic release. The response to GABA is mediated by GABAA receptors that respond to both phasic and tonic GABA release and that can produce excitatory as well as inhibitory cellular responses. GABA also influences circadian control through the exclusively inhibitory effects of GABAB receptors. Both GABA and neuropeptide signaling occur within the SCN, although the functional consequences of the interactions of these signals are not well understood. This review considers the role of GABA in the circadian pacemaker, in the mechanisms responsible for the generation of circadian rhythms, in the ability of non-photic stimuli to reset the phase of the pacemaker, and in the ability of the day-night cycle to entrain the pacemaker.
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Affiliation(s)
- H Elliott Albers
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States.
| | - James C Walton
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States
| | - Karen L Gamble
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - John K McNeill
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Neuroscience Institute, Georgia State University, Atlanta, GA 30302, United States
| | - Daniel L Hummer
- Center for Behavioral Neuroscience, Atlanta, GA 30302, United States; Department of Psychology, Morehouse College, Atlanta, GA 30314, United States
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13
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Özer FD, Öçmen E, Akan P, Erdost HA, Korkut S, Gökmen AN. Effect of Day and Night Desflurane Anaesthesia on Melatonin Levels in Rats. Turk J Anaesthesiol Reanim 2016; 44:190-194. [PMID: 27909592 PMCID: PMC5019869 DOI: 10.5152/tjar.2016.88609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 03/13/2016] [Indexed: 06/06/2023] Open
Abstract
OBJECTIVE The aim of this study is to investigate the effect of day and night administration of desflurane anaesthesia on melatonin levels in rats. METHODS Twenty-four 15-day-old rats were included in the study and were divided into four groups. The rats were anaesthetised between 19:00-01:00 (night group) and 07:00-13:00 (day group) with 5.7% desflurane concentration in 6 L min-1 100% oxygen. 6 L min-1 oxygen was administered to the control groups. At the end of 6 h of anaesthesia, blood samples were taken, and rats were sacrificed. Blood samples were centrifuged and melatonin levels from plasma samples were measured with radioimmunoassay. RESULTS There was a statistically significant difference between the groups (p=0.007). Between group day control and group night control there was a statistically significant difference (p=0.042). Further, there was a significant difference between group day control and night desfluran as well (p=0.024). We could not find any difference between other groups. CONCLUSION This study showed that 6 hours of 5.7% desflurane anaesthesia during day and night hours did not significantly change melatonin levels.
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Affiliation(s)
- Figen Datlı Özer
- Department of Anaesthesiology and Reanimation, Dokuz Eylül University School of Medicine, İzmir, Turkey
| | - Elvan Öçmen
- Department of Anaesthesiology and Reanimation, Dokuz Eylül University School of Medicine, İzmir, Turkey
| | - Pınar Akan
- Department of Biochemistry, Dokuz Eylül University School of Medicine, İzmir, Turkey
| | - Hale Aksu Erdost
- Department of Anaesthesiology and Reanimation, Dokuz Eylül University School of Medicine, İzmir, Turkey
| | - Sezen Korkut
- Department of Anaesthesiology and Reanimation, Dokuz Eylül University School of Medicine, İzmir, Turkey
| | - Ali Necati Gökmen
- Department of Anaesthesiology and Reanimation, Dokuz Eylül University School of Medicine, İzmir, Turkey
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Characterization of sevoflurane effects on Per2 expression using ex vivo bioluminescence imaging of the suprachiasmatic nucleus in transgenic rats. Neurosci Res 2016; 107:30-7. [DOI: 10.1016/j.neures.2015.11.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2015] [Revised: 11/28/2015] [Accepted: 11/30/2015] [Indexed: 01/11/2023]
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Kingsbury NJ, Taylor SR, Henson MA. Inhibitory and excitatory networks balance cell coupling in the suprachiasmatic nucleus: A modeling approach. J Theor Biol 2016; 397:135-44. [PMID: 26972478 DOI: 10.1016/j.jtbi.2016.02.039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 01/07/2016] [Accepted: 02/01/2016] [Indexed: 01/13/2023]
Abstract
Neuronal coupling contributes to circadian rhythms formation in the suprachiasmatic nucleus (SCN). While the neurotransmitter vasoactive intestinal polypeptide (VIP) is considered essential for synchronizing the oscillations of individual neurons, γ-aminobutyric acid (GABA) does not have a clear functional role despite being highly concentrated in the SCN. While most studies have examined the role of either GABA or VIP, our mathematical modeling approach explored their interplay on networks of SCN neurons. Tuning the parameters that control the release of GABA and VIP enabled us to optimize network synchrony, which was achieved at a peak firing rate during the subjective day of about 7Hz. Furthermore, VIP and GABA modulation could adjust network rhythm amplitude and period without sacrificing synchrony. We also performed simulations of SCN networks to phase shifts during 12h:12h light-dark cycles and showed that GABA networks reduced the average time for the SCN model to re-synchronize. We hypothesized that VIP and GABA balance cell coupling in the SCN to promote synchronization of heterogeneous oscillators while allowing flexibility for adjustment to environmental changes.
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Affiliation(s)
- Nathaniel J Kingsbury
- Department of Chemical Engineering, University of Massachusetts, Amherst, MA 01007, United States
| | - Stephanie R Taylor
- Department of Computer Science, Colby College, Waterville, ME 04901, United States
| | - Michael A Henson
- Department of Chemical Engineering, University of Massachusetts, Amherst, MA 01007, United States.
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16
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Moldavan M, Cravetchi O, Williams M, Irwin RP, Aicher SA, Allen CN. Localization and expression of GABA transporters in the suprachiasmatic nucleus. Eur J Neurosci 2015; 42:3018-32. [PMID: 26390912 DOI: 10.1111/ejn.13083] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 08/12/2015] [Accepted: 09/17/2015] [Indexed: 01/25/2023]
Abstract
GABA is a principal neurotransmitter in the suprachiasmatic hypothalamic nucleus (SCN), the master circadian clock. Despite the importance of GABA and GABA uptake for functioning of the circadian pacemaker, the localization and expression of GABA transporters (GATs) in the SCN has not been investigated. The present studies used Western blot analysis, immunohistochemistry and electron microscopy to demonstrate the presence of GABA transporter 1 (GAT1) and GAT3 in the SCN. By using light microscopy, GAT1 and GAT3 were co-localized throughout the SCN, but were not expressed in the perikarya of arginine vasopressin- or vasoactive intestinal peptide-immunoreactive (-ir) neurons of adult rats, nor in the neuronal processes labelled with the neurofilament heavy chain. Using electron microscopy, GAT1- and GAT3-ir was found in glial processes surrounding unlabelled neuronal perikarya, axons, dendrites, and enveloped symmetric and asymmetric axo-dendritic synapses. Glial fibrillary acidic protein-ir astrocytes grown in cell culture were immunopositive for GAT1 and GAT3 and both GATs could be observed in the same glial cell. These data demonstrate that synapses in the SCN function as 'tripartite' synapses consisting of presynaptic axon terminals, postsynaptic membranes and astrocytes that contain GABA transporters. This model suggests that astrocytes expressing both GATs may regulate the extracellular GABA, and thereby modulate the activity of neuronal networks in the SCN.
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Affiliation(s)
- Michael Moldavan
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Olga Cravetchi
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Melissa Williams
- Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
| | - Robert P Irwin
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR, 97239-3098, USA
| | - Sue A Aicher
- Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
| | - Charles N Allen
- Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Portland, OR, 97239-3098, USA.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
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17
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Gmeiner F, Kołodziejczyk A, Yoshii T, Rieger D, Nässel DR, Helfrich-Förster C. GABA(B) receptors play an essential role in maintaining sleep during the second half of the night in Drosophila melanogaster. ACTA ACUST UNITED AC 2014; 216:3837-43. [PMID: 24068350 DOI: 10.1242/jeb.085563] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
GABAergic signalling is important for normal sleep in humans and flies. Here we advance the current understanding of GABAergic modulation of daily sleep patterns by focusing on the role of slow metabotropic GABAB receptors in the fruit fly Drosophila melanogaster. We asked whether GABAB-R2 receptors are regulatory elements in sleep regulation in addition to the already identified fast ionotropic Rdl GABAA receptors. By immunocytochemical and reporter-based techniques we show that the pigment dispersing factor (PDF)-positive ventrolateral clock neurons (LNv) express GABAB-R2 receptors. Downregulation of GABAB-R2 receptors in the large PDF neurons (l-LNv) by RNAi reduced sleep maintenance in the second half of the night, whereas sleep latency at the beginning of the night that was previously shown to depend on ionotropic Rdl GABAA receptors remained unaltered. Our results confirm the role of the l-LNv neurons as an important part of the sleep circuit in D. melanogaster and also identify the GABAB-R2 receptors as the thus far missing component in GABA-signalling that is essential for sleep maintenance. Despite the significant effects on sleep, we did not observe any changes in circadian behaviour in flies with downregulated GABAB-R2 receptors, indicating that the regulation of sleep maintenance via l-LNv neurons is independent of their function in the circadian clock circuit.
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Affiliation(s)
- Florian Gmeiner
- Department of Neurobiology and Genetics, Theodor-Boveri Institute, Biocentre, University of Würzburg, Am Hubland, Würzburg D-97074, Germany
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Mori K, Iijima N, Higo S, Aikawa S, Matsuo I, Takumi K, Sakamoto A, Ozawa H. Epigenetic suppression of mouse Per2 expression in the suprachiasmatic nucleus by the inhalational anesthetic, sevoflurane. PLoS One 2014; 9:e87319. [PMID: 24498074 PMCID: PMC3909093 DOI: 10.1371/journal.pone.0087319] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2013] [Accepted: 12/20/2013] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND We previously reported that sevoflurane anesthesia reversibly suppresses the expression of the clock gene, Period2 (Per2), in the mouse suprachiasmatic nucleus (SCN). However, the molecular mechanisms underlying this suppression remain unclear. In this study, we examined the possibility that sevoflurane suppresses Per2 expression via epigenetic modification of the Per2 promoter. METHODS Mice were anesthetized with a gas mixture of 2.5% sevoflurane/40% oxygen at a 6 L/min flow for 1 or 4 h. After termination, brains were removed and samples of SCN tissue were derived from frozen brain sections. Chromatin immunoprecipitation (ChIP) assays using anti-acetylated-histone antibodies were performed to investigate the effects of sevoflurane on histone acetylation of the Per2 promoter. Interaction between the E'-box (a cis-element in the Per2 promoter) and CLOCK (the Clock gene product) was also assessed by a ChIP assay using an anti-CLOCK antibody. The SCN concentration of nicotinamide adenine dinucleotide (NAD(+)), a CLOCK regulator, was assessed by liquid chromatography-mass spectrometry. RESULTS Acetylation of histone H4 in the proximal region of the Per2 promoter was significantly reduced by sevoflurane. This change in the epigenetic profile of the Per2 gene was observed prior to suppression of Per2 expression. Simultaneously, a reduction in the CLOCK-E'-box interaction in the Per2 promoter was observed. Sevoflurane treatment did not affect the concentration of NAD(+) in the SCN. CONCLUSIONS Independent of NAD(+) concentration in the SCN, sevoflurane decreases CLOCK binding to the Per2 promoter E'-box motif, reducing histone acetylation and leading to suppression of Per2 expression.
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Affiliation(s)
- Keisuke Mori
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
- Department of Anesthesiology and Pain Medicine, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Norio Iijima
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Shimpei Higo
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Satoko Aikawa
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Izumi Matsuo
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
- Department of Anesthesiology and Pain Medicine, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Ken Takumi
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Atsuhiro Sakamoto
- Department of Anesthesiology and Pain Medicine, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Hitoshi Ozawa
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
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Anzai M, Iijima N, Higo S, Takumi K, Matsuo I, Mori K, Ohe Y, Kadota K, Akimoto T, Sakamoto A, Ozawa H. Direct and specific effect of sevoflurane anesthesia on rat Per2 expression in the suprachiasmatic nucleus. PLoS One 2013; 8:e59454. [PMID: 23555676 PMCID: PMC3605447 DOI: 10.1371/journal.pone.0059454] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 02/14/2013] [Indexed: 01/08/2023] Open
Abstract
Background Our previous studies revealed that application of the inhalation anesthetic, sevoflurane, reversibly repressed the expression of Per2 in the mouse suprachiasmatic nucleus (SCN). We aimed to examine whether sevoflurane directly affects the SCN. Methods We performed in vivo and in vitro experiments to investigate rat Per2 expression under sevoflurane-treatment. The in vivo effects of sevoflurane on rPer2 expression were examined by quantitative in situ hybridization with a radioactively-labeled cRNA probe. Additionally, we examined the effect of sevoflurane anesthesia on rest/activity rhythms in the rat. In the in vitro experiments, we applied sevoflurane to SCN explant cultures from Per2-dLuc transgenic rats, and monitored luciferase bioluminescence, representing Per2 promoter activity. Bioluminescence from two peripheral organs, the kidney cortex and the anterior pituitary gland, were also analyzed. Results Application of sevoflurane in rats significantly suppressed Per2 expression in the SCN compared with untreated animals. We observed no sevoflurane-induced phase-shift in the rest/activity rhythms. In the in vitro experiments, the intermittent application of sevoflurane repressed the increase of Per2-dLuc luminescence and led to a phase delay in the Per2-dLuc luminescence rhythm. Sevoflurane treatment did not suppress bioluminescence in the kidney cortex or the anterior pituitary gland. Conclusion The suppression of Per2-dLuc luminescence by sevoflurane in in vitro SCN cultures isolated from peripheral inputs and other nuclei suggest a direct action of sevoflurane on the SCN itself. That sevoflurane has no such effect on peripheral organs suggests that this action might be mediated through a neuron-specific cellular mechanism or a regulation of the signal transduction between neurons.
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Affiliation(s)
- Megumi Anzai
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
- Department of Anesthesiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
| | - Norio Iijima
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
- * E-mail:
| | - Shimpei Higo
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
| | - Ken Takumi
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
| | - Izumi Matsuo
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
- Department of Anesthesiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
| | - Keisuke Mori
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
- Department of Anesthesiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
| | - Yumiko Ohe
- Department of Anesthesiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
| | - Kana Kadota
- Department of Anesthesiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
| | - Toshio Akimoto
- Division of Laboratory Animal Science, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
| | - Atsuhiro Sakamoto
- Department of Anesthesiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
| | - Hitoshi Ozawa
- Department of Anatomy and Neurobiology, Graduate School of Medicine, Nippon Medical School, Bunkyo-ku, Tokyo, Japan
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Day or night administration of ketamine and pentobarbital differentially affect circadian rhythms of pineal melatonin secretion and locomotor activity in rats. Anesth Analg 2012; 115:805-13. [PMID: 22886841 DOI: 10.1213/ane.0b013e3182632bcb] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Surgery with general anesthesia disturbs circadian rhythms, which may lead to postoperative sleep disorders and delirium in patients. However, it is unclear how circadian rhythms are affected by different anesthetics administered at different times during the rest-activity cycle. We hypothesized that pentobarbital (an agonist at the γ-aminobutyric acid A receptors) and ketamine (an antagonist at the N-methyl-d-aspartate receptors) would have differential effects on circadian rhythms, and these effects would also be influenced by the time of their administration (the active versus resting phase). METHODS Rats were divided into 4 groups according to the anesthetic administered (pentobarbital or ketamine) and the timing of intraperitoneal administration (active/night phase or resting/day phase). Using online pineal microdialysis, we analyzed pineal melatonin secretion and locomotor activity rhythms in rats under a light/dark (12/12-hour) cycle for 5 days after anesthesia and microdialysis catheter implantation. The data were analyzed for rhythmicity by cosinor analysis. RESULTS Ketamine administered during the resting phase produced 65- and 153-minute phase advances, respectively, in melatonin secretion and locomotor activity rhythms on the first day after anesthesia. In contrast, ketamine administered during the active phase produced 43- and 235-minute phase delays. Pentobarbital had no effect on the phase of either melatonin secretion or locomotor activity, irrespective of the timing of administration. When administered during the active phase, both anesthetics decreased the amplitude of melatonin secretion on the day after anesthesia; when administered during the resting phase, however, neither anesthetic affected the amplitude. The amplitude of locomotor activity decreased in all animals for 3 days after anesthesia. CONCLUSION Ketamine has opposite phase-shifting effects on circadian rhythms according to the time of administration, whereas pentobarbital has no effect. Furthermore, both anesthetics decrease the postoperative amplitude of pineal melatonin secretion if administered during the active, but not the resting, phase of the 24-hour rest-activity cycle.
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van Oosterhout F, Lucassen EA, Houben T, vanderLeest HT, Antle MC, Meijer JH. Amplitude of the SCN clock enhanced by the behavioral activity rhythm. PLoS One 2012; 7:e39693. [PMID: 22761873 PMCID: PMC3386260 DOI: 10.1371/journal.pone.0039693] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 05/29/2012] [Indexed: 12/19/2022] Open
Abstract
Circadian rhythms are regulated by the suprachiasmatic nucleus (SCN), a small structure at the base of the hypothalamus. While light effects on the SCN are well established, little is known of behavioral effects. This study elucidates direct modulating action of behavioral activity on the SCN by use of in vivo electrophysiology recordings, assessments of general locomotor behavior, and video-tracking of mice. The results show suppression of SCN neuronal activity by spontaneous behavior, the magnitude being dependent on the intensity, duration and type of behavioral activity. The suppression was moderate (32% of circadian amplitude) for low-intensity behavior and considerable (59%) for locomotor activity. Mild manipulation of the animals had reversed effects on the SCN indicating that different mechanisms are involved in the regulatory effect of spontaneous versus induced activity. The results indicate that exercise at the proper time of the cycle can boost the amplitude of the rhythm of the SCN clock itself. This has potentially beneficial effects for other rhythmic functions that are under the control of the SCN.
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Affiliation(s)
- Floor van Oosterhout
- Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Eliane A. Lucassen
- Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Thijs Houben
- Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Henk Tjebbe vanderLeest
- Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
| | - Michael C. Antle
- Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
- Department of Psychology, Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Johanna H. Meijer
- Laboratory for Neurophysiology, Department of Molecular Cell Biology, Leiden University Medical Center, Leiden, The Netherlands
- * E-mail:
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Kubo Y, Tahara Y, Hirao A, Shibata S. 2,2,2-Tribromoethanol Phase-Shifts the Circadian Rhythm of the Liver Clock in Per2::Luciferase Knockin Mice: Lack of Dependence on Anesthetic Activity. J Pharmacol Exp Ther 2011; 340:698-705. [DOI: 10.1124/jpet.111.188615] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Vasalou C, Herzog E, Henson M. Multicellular model for intercellular synchronization in circadian neural networks. Biophys J 2011; 101:12-20. [PMID: 21723810 PMCID: PMC3127187 DOI: 10.1016/j.bpj.2011.04.051] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 03/22/2011] [Accepted: 04/18/2011] [Indexed: 12/22/2022] Open
Abstract
We developed a multicellular model characterized by a high degree of heterogeneity to investigate possible mechanisms that underlie circadian network synchronization and rhythmicity in the suprachiasmatic nucleus (SCN). We populated a two-dimensional grid with 400 model neurons coupled via γ-aminobutyric acid (GABA) and vasoactive intestinal polypeptide (VIP) neurotransmitters through a putative Ca(2+) mediated signaling cascade to investigate their roles in gene expression and electrical firing activity of cell populations. As observed experimentally, our model predicted that GABA would affect the amplitude of circadian oscillations but not synchrony among individual oscillators. Our model recapitulated experimental findings of decreased synchrony and average periods, loss of rhythmicity, and reduced circadian amplitudes as VIP signaling was eliminated. In addition, simulated increases of VIP reduced periodicity and synchrony. We therefore postulated a physiological range of VIP within which the system is able to produce sustained and synchronized oscillations. Our model recapitulated experimental findings of diminished amplitudes and periodicity with decreasing intracellular Ca(2+) concentrations, suggesting that such behavior could be due to simultaneous decrease of individual oscillation amplitudes and population synchrony. Simulated increases in Cl(-) levels resulted in increased Cl(-) influx into the cytosol, a decrease of inhibitory postsynaptic currents, and ultimately a shift of GABA-elicited responses from inhibitory to excitatory. The simultaneous reduction of IPSCs and increase in membrane resting potential produced GABA dose-dependent increases in firing rates across the population, as has been observed experimentally. By integrating circadian gene regulation and electrophysiology with intracellular and intercellular signaling, we were able to develop the first (to our knowledge) multicellular model that allows the effects of clock genes, electrical firing, Ca(2+), GABA, and VIP on circadian system behavior to be predicted.
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Affiliation(s)
- Christina Vasalou
- Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts
| | - Erik D. Herzog
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri
| | - Michael A. Henson
- Department of Chemical Engineering, University of Massachusetts, Amherst, Massachusetts
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A multiscale model to investigate circadian rhythmicity of pacemaker neurons in the suprachiasmatic nucleus. PLoS Comput Biol 2010; 6:e1000706. [PMID: 20300645 PMCID: PMC2837390 DOI: 10.1371/journal.pcbi.1000706] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2009] [Accepted: 02/05/2010] [Indexed: 01/28/2023] Open
Abstract
The suprachiasmatic nucleus (SCN) of the hypothalamus is a multicellular system that drives daily rhythms in mammalian behavior and physiology. Although the gene regulatory network that produces daily oscillations within individual neurons is well characterized, less is known about the electrophysiology of the SCN cells and how firing rate correlates with circadian gene expression. We developed a firing rate code model to incorporate known electrophysiological properties of SCN pacemaker cells, including circadian dependent changes in membrane voltage and ion conductances. Calcium dynamics were included in the model as the putative link between electrical firing and gene expression. Individual ion currents exhibited oscillatory patterns matching experimental data both in current levels and phase relationships. VIP and GABA neurotransmitters, which encode synaptic signals across the SCN, were found to play critical roles in daily oscillations of membrane excitability and gene expression. Blocking various mechanisms of intracellular calcium accumulation by simulated pharmacological agents (nimodipine, IP3- and ryanodine-blockers) reproduced experimentally observed trends in firing rate dynamics and core-clock gene transcription. The intracellular calcium concentration was shown to regulate diverse circadian processes such as firing frequency, gene expression and system periodicity. The model predicted a direct relationship between firing frequency and gene expression amplitudes, demonstrated the importance of intracellular pathways for single cell behavior and provided a novel multiscale framework which captured characteristics of the SCN at both the electrophysiological and gene regulatory levels. Circadian rhythms are ∼24 hour cycles in biochemical, physiological and behavioral processes observed in a diverse range of organisms including Cyanobacteria, Neurospora, Drosophila, mice and humans. In mammals, the dominant circadian pacemaker that drives daily rhythms is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN is composed of a highly connected network of ∼20,000 neurons. Within each individual SCN neuron core clock genes and proteins interact through intertwined regulatory loops to generate circadian oscillations on the molecular level. These neurons express daily rhythmicity in their firing frequency and other electrophysiological properties. The mechanisms by which the core clock produces synchronized rhythms in neural firing and gene expression are postulated to involve intracellular calcium, a second messenger that regulates many cellular processes. The interaction between the various clock components however remains unknown. In this paper, we present a single cell model that incorporates the circadian gene regulatory pathway, cellular electrophysiological properties, and cytosolic calcium dynamics. Our results suggest a possible system architecture that accounts for the robustness of the circadian clock at the single cell level. Our simulations predict a dual role for intracellular pathways instigated by intracellular calcium and VIP: maintaining the periodicity and amplitude of the core clock genes as well as the firing frequency oscillations.
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Hamada T, Shibata S. The role of GABAergic neuron on NMDA- and SP-induced phase delays in the suprachiasmatic nucleus neuronal activity rhythm in vitro. Neurosci Lett 2009; 468:344-7. [PMID: 19914338 DOI: 10.1016/j.neulet.2009.11.029] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Revised: 11/09/2009] [Accepted: 11/09/2009] [Indexed: 10/20/2022]
Abstract
Gamma-aminobutyric acid (GABA), and its biosynthetic enzyme, glutamic decarboxylase, are widely distributed in the suprachiasmatic nucleus (SCN). In the present study, we examined the role of the GABA(A) receptor on in vitro SCN responses to photic-like signals. We found that 100microM GABA(A) receptor antagonist bicuculline partially blocked field potentials evoked by optic nerve stimulation. NMDA- and SP-induced phase shifts of SCN neuronal activity rhythms, were blocked with 10microM bicuculline. Application of 100microM bicuculline alone induced phase advance of SCN neuronal activity rhythm. These results show that NMDA- and SP-induced phase shifts are blocked by bicuculline and suggest GABA has an important role as neurotransmitter in the neuronal network regulating phase shifts of the circadian clock.
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Affiliation(s)
- Toshiyuki Hamada
- Advanced Photonic Bioimaging Center, Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido 060-8638, Japan
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Legan SJ, Donoghue KM, Franklin KM, Duncan MJ. Phenobarbital blockade of the preovulatory luteinizing hormone surge: association with phase-advanced circadian clock and altered suprachiasmatic nucleus Period1 gene expression. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1620-30. [PMID: 19297538 DOI: 10.1152/ajpregu.90914.2008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The suprachiasmatic nucleus (SCN) controls the timing of the preovulatory luteinizing hormone (LH) surge in laboratory rodents. Barbiturate administration during a critical period on proestrus delays the surge and prolongs the estrous cycle 1 day. Because a nonphotic timing signal (zeitgeber) during the critical period that phase advances activity rhythms can also induce the latter effect, we hypothesized that barbiturates delay the LH surge by phase-advancing its circadian timing signal beyond the critical period. In experiment 1, locomotor rhythms and estrous cycles were monitored in hamsters for 2-3 wk preinjection and postinjection of vehicle or phenobarbital and after transfer to darkness at zeitgeber time (ZT) 6 on proestrus. Phenobarbital delayed estrous cycles in five of seven hamsters, which exhibited phase shifts that averaged twofold greater than those exhibited by vehicle controls or phenobarbital-injected hamsters with normal cycles. Experiment 2 used a similar protocol, but injections were at ZT 5, and blood samples for LH determination were collected from 1200 to 1800 on proestrus and the next day via jugular cannulae inserted the day before proestrus. Phenobarbital delayed the LH surge 1 day in all six hamsters, but it occurred at an earlier circadian time, supporting the above hypothesis. Experiment 3 investigated whether phenobarbital, like other nonphotic zeitgebers, suppresses SCN Period1 and Period2 transcription. Two hours postinjection, phenobarbital decreased SCN expression of only Period1 mRNA, as determined by in situ hybridization. These results suggest that phenobarbital advances the SCN pacemaker, governing activity rhythms and hormone release in part by decreasing its Period1 gene expression.
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Affiliation(s)
- Sandra J Legan
- Department of Physiology, University of Kentucky Medical Center, Lexington, KY 40536-0298, USA.
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Ehlen JC, Paul KN. Regulation of light's action in the mammalian circadian clock: role of the extrasynaptic GABAA receptor. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1606-12. [PMID: 19244580 DOI: 10.1152/ajpregu.90878.2008] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
GABA(A) receptor agonists act in the suprachiasmatic nucleus (SCN) to reset circadian rhythms during the day but inhibit the ability of light to reset rhythms during the night. In the present study, we examined whether these paradoxical differences in the effect of GABA(A) receptor stimulation on the circadian system are mediated by separate GABA(A) receptor subtypes. 4,5,6,7-Tetrahydroisoxazolo[5,4-c]pyridin-3-ol (THIP), a GABA(A) receptor agonist, preferentially activates GABA(A) receptors in extrasynaptic locations. THIP, muscimol (a GABA(A) agonist), or vehicle were microinjected into the SCN region of Syrian hamsters free-running in constant darkness during the mid-subjective day, early subjective night, or late subjective night. The subjective night injections were followed by a light pulse or sham control. Behavioral phase shifts of wheel running rhythms and both Period1 (Per1) and Per2 mRNA levels in the SCN were assessed. Animals that received THIP during the subjective day did not exhibit significant phase alterations. During the early and late subjective night, however, THIP abolished the phase-shifting effects of light and the ability of light to increase Per1 and Per2 mRNA levels. The ability of N-methyl-d-aspartic acid to phase-shift wheel running rhythms was also attenuated by THIP. Together these data demonstrate that THIP does not produce phase shifts during the subjective day, but does inhibit the ability of light to produce phase shifts. Thus, extrasynaptic GABA(A) receptors appear to play a role in regulating light input to the SCN, while a different population of GABA(A) receptors appears to be responsible for daytime effects of GABA.
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Affiliation(s)
- J Christopher Ehlen
- Circadian Rhythms and Sleep Disorders Program, Neuroscience Institute, Morehouse School of Medicine, Atlanta, GA 30310, USA
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Novak CM, Ehlen JC, Albers HE. Photic and nonphotic inputs to the diurnal circadian clock. BIOL RHYTHM RES 2008. [DOI: 10.1080/09291010701683482] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Serotonergic activation potentiates light resetting of the main circadian clock and alters clock gene expression in a diurnal rodent. Exp Neurol 2008; 210:501-13. [DOI: 10.1016/j.expneurol.2007.11.026] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Revised: 11/21/2007] [Accepted: 11/22/2007] [Indexed: 11/21/2022]
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Ehlen JC, Novak CM, Karom MC, Gamble KL, Albers HE. Interactions of GABA A receptor activation and light on period mRNA expression in the suprachiasmatic nucleus. J Biol Rhythms 2008; 23:16-25. [PMID: 18258754 DOI: 10.1177/0748730407310785] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Activation of gamma-aminobutyric acid (GABA) A receptors in the suprachiasmatic nucleus (SCN) resets the circadian clock during the day and inhibits the ability of light to reset the clock at night. Light in turn acts during the day to inhibit the phase-resetting effects of GABA. Some evidence suggests that Period mRNA changes in the SCN are responsible for these interactions between light and GABA. Here, the hypothesis that light and the GABA A receptor interact by altering the expression of Period 1 and/or Period 2 mRNA in the SCN is tested. The GABA A agonist muscimol was injected near the SCN just prior to a light pulse, during the mid-subjective day and the early and late subjective night. Changes in Period 1 and Period 2 mRNA were measured in the SCN by in situ hybridization. Light-induced Period 1 mRNA was inhibited by GABA A receptor activation in the early and late subjective night, while Period 2 mRNA was only inhibited during the late night. During the subjective day, light had no effect on the ability of muscimol to suppress Period 1 mRNA hybridization signal. Thus, light and GABA A receptor activation inhibit each other's ability to induce behavioral phase shifts throughout the subjective day and night. However, only in the late night are these behavioral effects correlated with changes in Period gene expression. Together, our data support the hypothesis that the interacting effects of light and GABA are the result of the opposing actions of these stimuli on Period mRNA, but only during the subjective night.
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Abstract
Daily rhythmicity, including timing of wakefulness and hormone secretion, is mainly controlled by a master clock located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN clockwork involves various clock genes, with specific temporal patterns of expression that are similar in nocturnal and diurnal species (e.g. the clock gene Per1 in the SCN peaks at midday in both categories). Timing of sensitivity to light is roughly similar, during nighttime, in diurnal and nocturnal species. Molecular mechanisms of photic resetting are also comparable in both species categories. By contrast, in animals housed in constant light, exposure to darkness can reset the SCN clock, mostly during the resting period, i.e. at opposite circadian times between diurnal and nocturnal species. Nonphotic stimuli, such as scheduled voluntary exercise, food shortage, exogenous melatonin, or serotonergic receptor activation, are also capable of shifting the master clock and/or modulating photic synchronization. Comparison between day- and night-active species allows classifications of nonphotic cues in two, arousal-independent and arousal-dependent, families of factors. Arousal-independent factors, such as melatonin (always secreted during nighttime, independently of daily activity pattern) or gamma-aminobutyric acid (GABA), have shifting effects at the same circadian times in both nocturnal and diurnal rodents. By contrast, arousal-dependent factors, such as serotonin (its cerebral levels follow activity pattern), induce phase shifts only during resting and have opposite modulating effects on photic resetting between diurnal and nocturnal species. Contrary to light and arousal-independent nonphotic cues, arousal-dependent nonphotic stimuli provide synchronizing feedback signals to the SCN clock in circadian antiphase between nocturnal and diurnal animals.
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Affiliation(s)
- Etienne Challet
- Department of Neurobiology of Rhythms, Institute of Cellular and Integrative Neurosciences, Centre National de la Recherche Scientifique (UMR 7168/LC2), University Louis Pasteur, 5 rue Blaise Pascal, Strasbourg, France.
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Novak CM, Ehlen JC, Paul KN, Fukuhara C, Albers HE. Light and GABAAreceptor activation alterPeriodmRNA levels in the SCN of diurnal Nile grass rats. Eur J Neurosci 2006; 24:2843-52. [PMID: 17156208 DOI: 10.1111/j.1460-9568.2006.05166.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We examined Period (Per) mRNA rhythms in the suprachiasmatic nucleus (SCN) of a diurnal rodent and assessed how phase-shifting stimuli acutely affect SCN Per mRNA using semiquantitative in situ hybridization. First, Per1 and Per2 varied rhythmically in the SCN over the course of one circadian cycle in constant darkness: Per1 mRNA was highest in the early to mid-subjective day, while Per2 mRNA levels peaked in the late subjective day. Second, acute light exposure in the early subjective night significantly increased both Per1 and Per2 mRNA. Third, Per2 but not Per1 levels decreased 1 and 2 h after injection of the gamma-aminobutyric acid (GABA)(A) receptor agonist muscimol into the SCN during the subjective day. Fourth, muscimol also reduced the light-induced Per2 in the early subjective night, but Per1 induction by light was not significantly affected. Consistent with previous studies, these data demonstrate that diurnal and nocturnal animals show very similar daily patterns of Per mRNA and light-induced Per increases in the SCN. As with light, muscimol alters circadian phase, and daytime phase alterations induced by muscimol are associated with significant decreases in Per2 mRNA. In diurnal animals, muscimol-induced decreases in Per are associated with phase delays rather than advances. The direction of the daytime phase shift may be determined by the relative suppression of Per1 vs. Per2 in SCN cells. As in nocturnal animals, changes in Per1 and Per2 mRNA by photic and non-photic stimuli appear to be associated with circadian phase alteration.
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Affiliation(s)
- Colleen M Novak
- Endocrine Research Unit, Mayo Clinic and Foundation, Rochester, MN, USA.
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