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Power A, Hughes ATL, Samuels RE, Piggins HD. Rhythm-promoting actions of exercise in mice with deficient neuropeptide signaling. J Biol Rhythms 2010; 25:235-46. [PMID: 20679493 DOI: 10.1177/0748730410374446] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Daily exercise promotes physical health as well as improvements in mental and neural functions. Studies in intact wild-type (WT) rodents have revealed that the brain's suprachiasmatic nuclei (SCN), site of the main circadian pacemaker, are also responsive to scheduled wheel running. It is unclear, however, if and how animals with a dysfunctional circadian pacemaker respond to exercise. Here, we tested whether scheduled voluntary exercise (SVE) in a running wheel for 6 hours per day could promote neural and behavioral rhythmicity in animals whose circadian competence is compromised through genetically targeted loss of vasoactive intestinal polypeptide (VIP(-/-) mice) or its VPAC(2) receptor (Vipr2(-/-) mice). We report that in constant dark (DD), rhythmic VIP(-/-) and Vipr2(-/-) mice show weak free-running rhythms with a period of <23 hours and all wild-type mice are strongly rhythmic with approximately 23.5-hour periodicity. VIP(-/-) and Vipr2(-/-) mice rapidly (<7 days) synchronize to daily SVE, while WT mice take much longer (>35 days). Following 21 to 50 days of SVE, WT mice show small changes in their rhythms, and most Vipr2(-/-) mice now sustain robust near 24-hour behavioral rhythms, whereas very few VIP(-/-) mice do. This study demonstrates that scheduled daily exercise can markedly improve circadian rhythms in behavioral activity and raises the possibility that this noninvasive approach may be useful as an intervention in clinical etiologies in which there are dysfunctions of circadian time keeping.
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Affiliation(s)
- A Power
- Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester, UK M13 9PT
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102
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Romero A, Potter MF, Haynes KF. Circadian rhythm of spontaneous locomotor activity in the bed bug, Cimex lectularius L. JOURNAL OF INSECT PHYSIOLOGY 2010; 56:1516-22. [PMID: 20452356 DOI: 10.1016/j.jinsphys.2010.04.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Revised: 04/23/2010] [Accepted: 04/30/2010] [Indexed: 05/26/2023]
Abstract
Bed bugs must avoid detection when finding hosts and returning to hidden harborages. Their stealthy habits include foraging when hosts are asleep. Characteristics of spontaneous locomotor activity rhythm of bed bugs with different feeding histories were studied. In the absence of host stimuli, adults and nymphs were much more active in the dark than in the light. The onset of activity in the scotophase commenced soon after lights-off. The free-running period (tau) for all stages was longer in continuous darkness (DD) than in continuous light (LL). The lengthening of tau in DD is an exception for the circadian rule that predicts the opposite in nocturnal animals. Activity in all stages was entrained to reverse L:D regimes within four cycles. Short-term starved adults moved more frequently than recently fed adults. While bed bugs can survive for a year or more without a blood meal, we observed a reduction in activity in insects held for five weeks without food. We suggest that bed bugs make a transition to host-stimulus dependent searching when host presence is not predictable. Such a strategy would enable bed bugs to maximize reproduction when resources are abundant and save energy when resources are scarce.
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Affiliation(s)
- Alvaro Romero
- Department of Entomology, University of Kentucky, Lexington, KY 40546, USA.
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103
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Gopar-Canales KL, Miranda-Anaya M, Moreno-Sáenz E, Barrera-Mera B. Circadian locomotor activity in the juvenile red eared turtleTrachemys scripta elegans: free running and entrainment. BIOL RHYTHM RES 2010. [DOI: 10.1080/09291010903214813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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104
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Challet E, Mendoza J. Metabolic and reward feeding synchronises the rhythmic brain. Cell Tissue Res 2010; 341:1-11. [DOI: 10.1007/s00441-010-1001-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Accepted: 05/28/2010] [Indexed: 12/28/2022]
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105
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Glickman G. Circadian rhythms and sleep in children with autism. Neurosci Biobehav Rev 2010; 34:755-68. [PMID: 19963005 DOI: 10.1016/j.neubiorev.2009.11.017] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 11/17/2009] [Accepted: 11/18/2009] [Indexed: 01/08/2023]
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106
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Sans-Fuentes MA, Díez-Noguera A, Cambras T. Light responses of the circadian system in leptin deficient mice. Physiol Behav 2010; 99:487-94. [DOI: 10.1016/j.physbeh.2009.12.023] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 11/25/2009] [Accepted: 12/17/2009] [Indexed: 01/19/2023]
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107
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Interactions between light, mealtime and calorie restriction to control daily timing in mammals. J Comp Physiol B 2010; 180:631-44. [PMID: 20174808 DOI: 10.1007/s00360-010-0451-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2009] [Revised: 01/21/2010] [Accepted: 01/26/2010] [Indexed: 10/19/2022]
Abstract
Daily variations in behaviour and physiology are controlled by a circadian timing system consisting of a network of oscillatory structures. In mammals, a master clock, located in the suprachiasmatic nuclei (SCN) of the hypothalamus, adjusts timing of other self-sustained oscillators in the brain and peripheral organs. Synchronisation to external cues is mainly achieved by ambient light, which resets the SCN clock. Other environmental factors, in particular food availability and time of feeding, also influence internal timing. Timed feeding can reset the phase of the peripheral oscillators whilst having almost no effect in shifting the phase of the SCN clockwork when animals are exposed (synchronised) to a light-dark cycle. Food deprivation and calorie restriction lead not only to loss of body mass (>15%) and increased motor activity, but also affect the timing of daily activity, nocturnal animals becoming partially diurnal (i.e. they are active during their usual sleep period). This change in behavioural timing is due in part to the fact that metabolic cues associated with calorie restriction affect the SCN clock and its synchronisation to light.
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108
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Bartoszewicz R, Barbacka-Surowiak G. The phase shift of locomotor activity rhythm after application of 8-OH-DPAT under constant light in mice. BIOL RHYTHM RES 2010. [DOI: 10.1080/09291010802568723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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109
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Jayakumar M, Arul D, Prahalathan P, Subramanian P. Night-time food restriction modulates the circadian patterns of redox status in rats. BIOL RHYTHM RES 2010. [DOI: 10.1080/09291010802568772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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110
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Webb IC, Patton DF, Landry GJ, Mistlberger RE. Circadian clock resetting by behavioral arousal: neural correlates in the midbrain raphe nuclei and locus coeruleus. Neuroscience 2010; 166:739-51. [PMID: 20079808 DOI: 10.1016/j.neuroscience.2010.01.014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2008] [Revised: 01/07/2010] [Accepted: 01/08/2010] [Indexed: 10/19/2022]
Abstract
Some procedures for stimulating arousal in the usual daily rest period (e.g., gentle handling, novel wheel-induced running) can phase shift circadian rhythms in Syrian hamsters, while other arousal procedures are ineffective (inescapable stress, caffeine, modafinil). The dorsal and median raphe nuclei (DRN, MnR) have been implicated in clock resetting by arousal and, in rats and mice, exhibit strong regionally specific responses to inescapable stress and anxiogenic drugs. To examine a possible role for the midbrain raphe nuclei in the differential effects of arousal procedures on circadian rhythms, hamsters were aroused for 3 h in the mid-rest period by confinement to a novel running wheel, gentle handling (with minimal activity) or physical restraint (with intermittent, loud compressed air stimulation) and sacrificed immediately thereafter. Regional expression of c-fos and tryptophan hydroxylase (TrpOH) were quantified immunocytochemically in the DRN, MnR and locus coeruleus (LC). Neither gentle handling nor wheel running had a large impact on c-fos expression in these areas, although the manipulations were associated with a small increase in c-Fos in TrpOH-like and TrpOH-negative cells, respectively, in the caudal interfascicular DRN region. By contrast, restraint stress significantly increased c-Fos in both TrpOH-like and TrpOH-negative cells in the rostral DRN and LC. c-Fos-positive cells in the DRN did not express tyrosine hydroxylase. These results reveal regionally specific monoaminergic correlates of arousal-induced circadian clock resetting, and suggest a hypothesis that strong activation of some DRN and LC neurons by inescapable stress may oppose clock resetting in response to arousal during the daily sleep period. More generally, these results complement evidence from other rodent species for functional topographic organization of the DRN.
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Affiliation(s)
- I C Webb
- Department of Psychology, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
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111
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112
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Gillman AG, Leffel JK, Kosobud AEK, Timberlake W. Fentanyl, but not haloperidol, entrains persisting circadian activity episodes when administered at 24- and 31-h intervals. Behav Brain Res 2009; 205:102-14. [PMID: 19595707 PMCID: PMC2755526 DOI: 10.1016/j.bbr.2009.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 06/30/2009] [Accepted: 07/02/2009] [Indexed: 02/01/2023]
Abstract
Administration of several drugs of abuse on a 24-h schedule has been shown to entrain both pre-drug (anticipatory) and post-drug (evoked) circadian activity episodes that persist for several days when the drug is withheld. The present study tested the entrainment effects of fentanyl, an opioid agonist with a noted abuse liability, and haloperidol, an anti-psychotic dopamine antagonist without apparent abuse liability. Adult female Sprague-Dawley rats housed under constant light in cages with attached running wheels received repeated low, medium, or high doses of either fentanyl or haloperidol on a 24-h administration schedule followed by a 31-h schedule (Experiment 1) or solely on a 31-h schedule (Experiment 2). The results showed that all three doses of fentanyl entrained both pre-drug and post-drug episodes of wheel running when administered every 24h, and the combined pre- and post-fentanyl activity episodes persisted for at least 3 days when the drug was withheld during test days. On the 31-h schedule, fentanyl produced an "ensuing" activity episode approximately 24h post-administration, but failed to produce an anticipatory episode 29-31h post-administration. In contrast, haloperidol injections failed to produce both pre-drug episodes on the 24-h schedule and circadian ensuing episodes on the 31-h schedule, and post-haloperidol suppression of activity appeared to mask the free-running activity rhythm. Taken together, these results provide additional evidence that drugs of abuse share a common ability to entrain circadian activity episodes.
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Affiliation(s)
- Andrea G Gillman
- Department of Psychological and Brain Sciences, Indiana University, Bloomington, United States.
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113
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Amir S, Stewart J. Behavioral and hormonal regulation of expression of the clock protein, PER2, in the central extended amygdala. Prog Neuropsychopharmacol Biol Psychiatry 2009; 33:1321-8. [PMID: 19376186 DOI: 10.1016/j.pnpbp.2009.04.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Accepted: 04/01/2009] [Indexed: 11/30/2022]
Abstract
PER2, a key molecular component of the mammalian circadian clock, is expressed rhythmically in many brain areas and peripheral tissues in mammals. Here we review findings from our work on the nature and regulation of rhythms of expression of PER2 in two anatomically and neurochemically defined subregions of the central extended amygdala, the oval nucleus of the bed nucleus of the stria terminalis (BNSTov) and the central nucleus of the amygdala (CEA). Daily rhythms in the expression of PER2 in these regions are coupled to those of the master circadian pacemaker, the suprachiasmatic nucleus (SCN) but, importantly, they are sensitive to homeostatic perturbations and to hormonal states that directly influence motivated behavior.
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Affiliation(s)
- Shimon Amir
- Center for Studies in Behavioral Neurobiology/Groupe de Recherche en Neurobiologie Comportementale, Department of Psychology, Concordia University, Montreal, QC, Canada.
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114
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Hauzenberger AR, Gebhardt-Henrich SG, Steiger A, Weinert D, Gattermann† R. Desynchronisation of circadian activity rhythms in golden hamsters (Mesocricetus auratus) housed in deep bedding. BIOL RHYTHM RES 2009. [DOI: 10.1080/09291010902731171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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115
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Hauzenberger AR, Gebhardt-Henrich SG, Steiger A. Activity measurement by three different techniques in golden hamsters (Mesocricetus auratus): a comparison between burrow systems and standard cages. BIOL RHYTHM RES 2009. [DOI: 10.1080/09291010902731197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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116
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Functional neuroanatomy of sleep and circadian rhythms. ACTA ACUST UNITED AC 2009; 61:281-306. [PMID: 19695288 DOI: 10.1016/j.brainresrev.2009.08.001] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 07/02/2009] [Accepted: 08/07/2009] [Indexed: 11/23/2022]
Abstract
The daily sleep-wake cycle is perhaps the most dramatic overt manifestation of the circadian timing system, and this is especially true for the monophasic sleep-wake cycle of humans. Considerable recent progress has been made in elucidating the neurobiological mechanisms underlying sleep and arousal, and more generally, of circadian rhythmicity in behavioral and physiological systems. This paper broadly reviews these mechanisms from a functional neuroanatomical and neurochemical perspective, highlighting both historical and recent advances. In particular, I focus on the neural pathways underlying reciprocal interactions between the sleep-regulatory and circadian timing systems, and the functional implications of these interactions. While these two regulatory systems have often been considered in isolation, sleep-wake and circadian regulation are closely intertwined processes controlled by extensively integrated neurobiological mechanisms.
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117
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Legates TA, Dunn D, Weber ET. Accelerated re-entrainment to advanced light cycles in BALB/cJ mice. Physiol Behav 2009; 98:427-32. [PMID: 19619568 DOI: 10.1016/j.physbeh.2009.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Revised: 07/02/2009] [Accepted: 07/10/2009] [Indexed: 10/20/2022]
Abstract
Circadian rhythms in mammals are coordinated by the suprachiasmatic nuclei (SCN) of the hypothalamus, which are most potently synchronized to environmental light-dark cycles. Large advances in the light-dark cycle typically yield gradual advances in activity rhythms on the order of 1-2h per day until re-entrainment is complete due to limitations on the circadian system which are not yet understood. In humans, this delay until re-entrainment is accomplished is experienced as jetlag, with accompanying symptoms of malaise, decreased cognitive performance, sleep problems and gastrointestinal distress. In these experiments, locomotor rhythms of BALB/cJ mice monitored by running wheels were shown to re-entrain to large 6- or 8-hour shifts of the light-dark cycle within 1-2 days, as opposed to the 5-7 days required for C57BL/6J mice. A single-day 6-hour advance of the LD cycle followed by release to constant darkness yielded similar phase shifts, demonstrating that exaggerated re-entrainment is not explained by masking of activity by the light-dark cycle. Responses in BALB/cJ mice were similar when monitored instead by motion detectors, indicating that wheel-running exercise does not influence the magnitude of responses. Neither brief (15 min) light exposure late during subjective nighttime nor 6-hour delays of the light-dark cycle produced exaggerated locomotor phase shifts, indicating that BALB/cJ mice do not merely experience enhanced sensitivity to light. Fos protein was expressed in cells of the SCN following acute light exposure at ZT10 of their previous light-dark cycle, a normally non-responsive time in the circadian cycle, but only in BALB/cJ (and not C57BL/6J) mice that had been subjected two days earlier to a single-day 6-hour advance of the light-dark cycle, indicating that their SCN had been advanced by that treatment. BALB/cJ mice may thus serve as a useful comparative model for studying molecular and physiological processes that limit responsiveness of circadian clocks to photic input.
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118
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Weinert D, Schottner K. An Inbred Lineage of Djungarian Hamsters with a Strongly Attenuated Ability to Synchronize. Chronobiol Int 2009; 24:1065-79. [DOI: 10.1080/07420520701791588] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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119
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Scherbarth F, Steinlechner S. The Annual Activity Pattern of Djungarian Hamsters (Phodopus sungorus) Is Affected by Wheel‐Running Activity. Chronobiol Int 2009; 25:905-22. [DOI: 10.1080/07420520802544514] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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120
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Scheibler E, Wollnik F. Interspecific contact affects phase response and activity in Desert hamsters. Physiol Behav 2009; 98:288-95. [PMID: 19524601 DOI: 10.1016/j.physbeh.2009.06.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 05/29/2009] [Accepted: 06/04/2009] [Indexed: 11/29/2022]
Abstract
Circadian rhythms enhance survival and reproductive fitness of animals by promoting optimal timing of behavior and physiology with reference to geophysical changes in environment. Although light is considered the dominant stimulus for entraining circadian rhythms, social stimuli can also act as zeitgebers. The aim of this study was to analyze how Desert hamsters (Phodopus roborovskii) coordinate their behavior in time with that of animals of another competing species (Mongolian gerbils, Meriones unguiculatus). First, the behavior of hamsters was analyzed during a step-wise avoidance test. Two effects were observed: a) spatial separation if it was possible or b) shortening of the activity period due to contact without chance for avoidance. The latter finding was now further analyzed using a phase response curve (PRC). Here, phase shifts of Desert hamsters caused by single social interactions with Mongolian gerbils were quantified. Phase advances during the rest period were found at CT3 and CT9, a similar tendency was observed at CT6. A second phase advance was determined at CT18, coinciding with the end of the activity period. Then, it was tested whether additional activity during the stimulus was a trigger for the phase response. Although an increase in activity occurred especially when stimuli were applied during the rest period, there was no general relation between additional activity measured and the phase response shown. Overall, relevance of interspecific contact as nonphotic zeitgeber was indicated by phase shifts in a phase response curve. The shape of it can be explained by two behavioral adaptations; stress and contact avoidance.
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Affiliation(s)
- Elke Scheibler
- University Stuttgart, Biological Institute, Dept. of Animal Physiology, Pfaffenwaldring 57, D - 70569 Stuttgart, Germany.
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121
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Cuesta M, Clesse D, Pévet P, Challet E. New light on the serotonergic paradox in the rat circadian system. J Neurochem 2009; 110:231-43. [PMID: 19457131 DOI: 10.1111/j.1471-4159.2009.06128.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The main mammalian circadian clock, localized in the suprachiasmatic nuclei can be synchronized not only with light, but also with serotonergic activation. Serotonergic agonists and serotonin reuptake inhibitors (e.g., fluoxetine) have a non-photic influence (shifting effects during daytime and attenuation of photic resetting during nighttime) on hamsters' and mice' main clock. Surprisingly, in rats serotonergic modulation of the clock shows essentially photic-like features in vivo (shifting effects during nighttime). To delineate this apparent paradox, we analyzed the effects of fluoxetine and serotonin agonists on rats' clock. First, fluoxetine induced behavioral phase-advances associated with down-regulated expression of the clock genes Per1 and Rorbeta and up-regulated expression of Rev-erbalpha during daytime. Moreover, fluoxetine produced an attenuation of light-induced phase-advances in association with altered expression of Per1, Per2 and Rorbeta during nighttime. Second, we showed that 5-HT(1A) receptors -maybe with co-activation of 5-HT(7) receptors- were implicated in non-photic effects on the main clock. By contrast, 5-HT(3) and 5-HT(2C) receptors were involved in photic-like effects and, for 5-HT(2C) subtype only, in potentiation of photic resetting. Thus this study demonstrates that as for other nocturnal rodents, a global activation of the serotonergic system induces non-photic effects in the rats' clock during daytime and nighttime.
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Affiliation(s)
- Marc Cuesta
- Département de Neurobiologie des Rythmes, Institut de Neurosciences Cellulaires et Intégratives, UPR3212, Centre National de la Recherche Scientifique, Université de Strasbourg, Strasbourg, France
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122
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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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123
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Smith VM, Baserman JN, Hagel K, Teskey GC, Antle MC. A single generalized seizure alters the amplitude, but not phase, of the circadian activity rhythm of the hamster. Chronobiol Int 2009; 26:1-13. [PMID: 19142754 DOI: 10.1080/07420520802694103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
People with epilepsy exhibit high rates of sleep disturbances. In many cases, these sleep disruptions appear to be related to the occurrence of the seizures themselves. Changes in sleep structure may reflect underlying changes in the circadian clock, as circadian rhythms of locomotor activity, body temperature, and hormone release are disrupted following a seizure. The present study was designed to determine if a single generalized seizure could alter the phase and waveform of the circadian rhythm of wheel-running behavior in the Syrian hamster. Animals were housed in constant darkness, and were administered either a sham treatment or a maximal electroconvulsive shock at one of three time-points: 6 h before activity onset, 1 h after activity onset, or 6 h after activity onset. Seizures at all of these phases did not significantly affect the phase of the circadian activity rhythm. The circadian locomotor activity levels were significantly attenuated following seizures at all three phases. This attenuation was prominent over the 24 h following the seizure, and was also evident over the three post-seizure days. These data suggest that while seizures do not affect phase, they may alter the amplitude of the circadian clock. Because the amplitude of the circadian clock affects sleep quality, these findings suggest one mechanism by which persistent seizures may decrease the quality of sleep in patients with epilepsy.
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Affiliation(s)
- Victoria M Smith
- Department of Psychology, University of Calgary, Calgary, AB, Canada
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124
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Mendoza J, Pévet P, Challet E. Entrainment and coupling of the hamster suprachiasmatic clock by daily dark pulses. J Neurosci Res 2009; 87:758-65. [DOI: 10.1002/jnr.21887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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125
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Moura PJ, Gimenes-Júnior JA, Valentinuzzi VS, Xavier GF. Circadian phase and intertrial interval interfere with social recognition memory. Physiol Behav 2009; 96:51-6. [DOI: 10.1016/j.physbeh.2008.08.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Revised: 08/11/2008] [Accepted: 08/14/2008] [Indexed: 11/25/2022]
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126
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Marston OJ, Williams RH, Canal MM, Samuels RE, Upton N, Piggins HD. Circadian and dark-pulse activation of orexin/hypocretin neurons. Mol Brain 2008; 1:19. [PMID: 19055781 PMCID: PMC2632999 DOI: 10.1186/1756-6606-1-19] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Accepted: 12/03/2008] [Indexed: 01/03/2024] Open
Abstract
Temporal control of brain and behavioral states emerges as a consequence of the interaction between circadian and homeostatic neural circuits. This interaction permits the daily rhythm of sleep and wake, regulated in parallel by circadian cues originating from the suprachiasmatic nuclei (SCN) and arousal-promoting signals arising from the orexin-containing neurons in the tuberal hypothalamus (TH). Intriguingly, the SCN circadian clock can be reset by arousal-promoting stimuli while activation of orexin/hypocretin neurons is believed to be under circadian control, suggesting the existence of a reciprocal relationship. Unfortunately, since orexin neurons are themselves activated by locomotor promoting cues, it is unclear how these two systems interact to regulate behavioral rhythms. Here mice were placed in conditions of constant light, which suppressed locomotor activity, but also revealed a highly pronounced circadian pattern in orexin neuronal activation. Significantly, activation of orexin neurons in the medial and lateral TH occurred prior to the onset of sustained wheel-running activity. Moreover, exposure to a 6 h dark pulse during the subjective day, a stimulus that promotes arousal and phase advances behavioral rhythms, activated neurons in the medial and lateral TH including those containing orexin. Concurrently, this stimulus suppressed SCN activity while activating cells in the median raphe. In contrast, dark pulse exposure during the subjective night did not reset SCN-controlled behavioral rhythms and caused a transient suppression of neuronal activation in the TH. Collectively these results demonstrate, for the first time, pronounced circadian control of orexin neuron activation and implicate recruitment of orexin cells in dark pulse resetting of the SCN circadian clock.
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127
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Mendes AL, Menezes AA, Azevedo CV. The influence of social cues on circadian activity rhythm resynchronisation to the light–dark cycle in common marmosetsCallithrix jacchus. BIOL RHYTHM RES 2008. [DOI: 10.1080/09291010701682658] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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128
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Brown T, Coogan A, Cutler D, Hughes A, Piggins H. Electrophysiological actions of orexins on rat suprachiasmatic neurons in vitro. Neurosci Lett 2008; 448:273-8. [DOI: 10.1016/j.neulet.2008.10.058] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 10/16/2008] [Accepted: 10/17/2008] [Indexed: 11/26/2022]
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129
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Antle MC, Tse F, Koke SJ, Sterniczuk R, Hagel K. Non-photic phase shifting of the circadian clock: role of the extracellular signal-responsive kinases I/II/mitogen-activated protein kinase pathway. Eur J Neurosci 2008; 28:2511-8. [DOI: 10.1111/j.1460-9568.2008.06533.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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130
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Katz ME, Simonetta SH, Ralph MR, Golombek DA. Immunosuppressant calcineurin inhibitors phase shift circadian rhythms and inhibit circadian responses to light. Pharmacol Biochem Behav 2008; 90:763-8. [PMID: 18590756 DOI: 10.1016/j.pbb.2008.05.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Revised: 05/06/2008] [Accepted: 05/27/2008] [Indexed: 11/16/2022]
Abstract
PP2B is a Ca2+/calmodulin-dependent protein phosphatase that is ubiquitously expressed in mammals. Among other actions, it is an effector mechanism in NMDA-mediated glutamate neurotransmission as well as a regulator of GSK3beta and MAPK signaling cascades. Because all of these mechanisms have demonstrable roles in the control of circadian rhythyms, we hypothesized that PP2B would be a key regulator of rhythm generation and entrainment, and that through inhibition of its phosphatase activity, the circadian system would be affected by immunosuppressant drug therapy. We report here that immunosuppressant drugs (cyclosporin A, FK506) (1) block the circadian responses to light that underlie photic entrainment; (2) produce circadian phase shifts with a characteristic nonphotic profile; and (3) disrupt circadian rhythm expression when applied chronically. These results indicate a role for PP2B in circadian rhythm generation and entrainment. In addition, because rhythm disturbance has been implicated in impairment of both physical and mental health, we suggest that the use of immunosuppressants would be safer and more efficacious if their impacts on circadian rhythmicity were taken into account.
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Affiliation(s)
- Marcelo E Katz
- Laboratorio de Cronobiología, Departamento de Ciencia y Tecnología, Universidad Nacional de Quilmes/CONICET, Buenos Aires, Argentina
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131
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Indic P, Schwartz WJ, Paydarfar D. Design principles for phase-splitting behaviour of coupled cellular oscillators: clues from hamsters with 'split' circadian rhythms. J R Soc Interface 2008; 5:873-83. [PMID: 18077247 PMCID: PMC2607461 DOI: 10.1098/rsif.2007.1248] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Nonlinear interactions among coupled cellular oscillators are likely to underlie a variety of complex rhythmic behaviours. Here we consider the case of one such behaviour, a doubling of rhythm frequency caused by the spontaneous splitting of a population of synchronized oscillators into two subgroups each oscillating in anti-phase (phase-splitting). An example of biological phase-splitting is the frequency doubling of the circadian locomotor rhythm in hamsters housed in constant light, in which the pacemaker in the suprachiasmatic nucleus (SCN) is reconfigured with its left and right halves oscillating in anti-phase. We apply the theory of coupled phase oscillators to show that stable phase-splitting requires the presence of negative coupling terms, through delayed and/or inhibitory interactions. We also find that the inclusion of real biological constraints (that the SCN contains a finite number of non-identical noisy oscillators) implies the existence of an underlying non-uniform network architecture, in which the population of oscillators must interact through at least two types of connections. We propose that a key design principle for the frequency doubling of a population of biological oscillators is inhomogeneity of oscillator coupling.
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Affiliation(s)
- Premananda Indic
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA
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132
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Smith VM, Sterniczuk R, Phillips CI, Antle MC. Altered photic and non-photic phase shifts in 5-HT(1A) receptor knockout mice. Neuroscience 2008; 157:513-23. [PMID: 18930788 DOI: 10.1016/j.neuroscience.2008.09.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Revised: 09/17/2008] [Accepted: 09/18/2008] [Indexed: 11/30/2022]
Abstract
The mammalian circadian clock located in the suprachiasmatic nucleus (SCN) is thought to be modulated by 5-HT. 5-HT is though to inhibit photic phase shifts by inhibiting the release of glutamate from retinal terminals, as well as by decreasing the responsiveness of retinorecipient cells in the SCN. Furthermore, there is also evidence that 5-HT may underlie, in part, non-photic phase shifts of the circadian system. Understanding the mechanism by which 5-HT accomplishes these goals is complicated by the wide variety of 5-HT receptors found in the SCN, the heterogeneous organization of both the circadian clock and the location of 5-HT receptors, and by a lack of sufficiently selective pharmacological agents for the 5-HT receptors of interest. Genetically modified animals engineered to lack a specific 5-HT receptor present an alternative avenue of investigation to understand how 5-HT regulates the circadian system. Here we examine behavioral and molecular responses to both photic and non-photic stimuli in mice lacking the 5-HT(1A) receptor. When compared with wild-type controls, these mice exhibit larger phase advances to a short late-night light pulse and larger delays to long 12 h light pulses that span the whole subjective night. Fos and mPer1 expression in the retinorecipient SCN is significantly attenuated following late-night light pulses in the 5-HT(1A) knockout animals. Finally, non-photic phase shifts to (+/-)-8-hydroxy-2-(dipropylamino)tetralin hydrobromide (8-OH-DPAT) are lost in the knockout animals, while attenuation of the phase shift to the long light pulse due to rebound activity following a wheel lock is unaffected. These findings suggest that the 5-HT(1A) receptor plays an inhibitory role in behavioral phase shifts, a facilitatory role in light-induced gene expression, a necessary role in phase shifts to 8-OH-DPAT, and is not necessary for activity-induced phase advances that oppose photic phase shifts to long light pulses.
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Affiliation(s)
- V M Smith
- Department of Psychology, University of Calgary, 2500 University Drive Northwest, Calgary, Alberta, Canada T2N 1N4
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133
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Paul MJ, Schwartz WJ. On the chronobiology of cohabitation. COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 2008; 72:615-21. [PMID: 18419321 DOI: 10.1101/sqb.2007.72.042] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Social regulation of animal circadian rhythms may enable individuals in a population to temporally synchronize or segregate their activities within the community. Relatively little is known about the mechanisms for such interindividual temporal adaptations or how the circadian system might be involved. The literature suggests that actual prolonged cohabitation might lead to robust effects on the rhythmicity of cohoused individuals but that these effects are not easily reproduced by indirect or pulsatile social contacts. We have begun to study the conditions under which such cohabitation effects might be revealed in the laboratory, and we present and discuss initial data that cohousing pairs of golden hamsters can result in a persistent change in the free-running circadian period of one of the two hamsters of the pair. We believe that analyzing the societal level of temporal organization, and ultimately dissecting its underlying mechanisms, will enrich our understanding of the circadian clock and its role in establishing ecological communities.
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Affiliation(s)
- M J Paul
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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134
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Cannabinoids and hamster circadian activity rhythms. Brain Res 2008; 1222:141-8. [DOI: 10.1016/j.brainres.2008.05.048] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Revised: 05/19/2008] [Accepted: 05/20/2008] [Indexed: 11/18/2022]
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135
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Angeles-Castellanos M, Salgado-Delgado R, Rodríguez K, Buijs RM, Escobar C. Expectancy for food or expectancy for chocolate reveals timing systems for metabolism and reward. Neuroscience 2008; 155:297-307. [PMID: 18585440 DOI: 10.1016/j.neuroscience.2008.06.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 06/02/2008] [Accepted: 06/02/2008] [Indexed: 10/22/2022]
Abstract
The clock gene protein Per 1 (PER1) is expressed in several brain structures and oscillates associated with the suprachiasmatic nucleus (SCN). Restricted feeding schedules (RFS) induce anticipatory activity and impose daily oscillations of c-Fos and clock proteins in brain structures. Daily access to a palatable treat (chocolate) also elicits anticipatory activity and induces c-Fos expression mainly in corticolimbic structures. Here the influence of daily access to food or chocolate was explored by the analysis of the oscillatory patterns of PER1 in hypothalamic and corticolimbic structures. Wistar rats were exposed to RFS or to daily access to chocolate for 3 weeks. Persistence of food or chocolate entrained rhythms was determined 8 days after cessation of the feeding protocols. RFS and chocolate induced a phase shift in PER1 rhythmicity in corticolimbic structures with peak values at zeitgeber time 12 and a higher amplitude in the chocolate group. Both RFS and chocolate groups showed an upregulation of PER1 in the SCN. Food and chocolate entrained rhythms persisted for 8 days in behavior and in PER1 expression in the dorsomedial hypothalamic nucleus, accumbens, prefrontal cortex and central amygdala. The present data demonstrate the existence of different oscillatory systems in the brain that can be activated by entrainment to metabolic stimuli or to reward and suggest the participation of PER1 in both entraining pathways. Persistence and amplification of PER1 oscillations in structures associated with reward suggest that this oscillatory process is fundamental to food addictive behavior.
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Affiliation(s)
- M Angeles-Castellanos
- Departamento de Anatomía, Fac de Medicina Universidad Nacional Autónoma de México, México, Mexico
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136
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Kronfeld-Schor N, Dayan T. Activity patterns of rodents: the physiological ecology of biological rhythms. BIOL RHYTHM RES 2008. [DOI: 10.1080/09291010701683268] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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137
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Mendoza J, Clesse D, Pévet P, Challet E. Serotonergic potentiation of dark pulse-induced phase-shifting effects at midday in hamsters. J Neurochem 2008; 106:1404-14. [PMID: 18498439 DOI: 10.1111/j.1471-4159.2008.05493.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In mammals, resetting of the suprachiasmatic clock (SCN) by behavioral activation or serotonin (5-HT) agonists is mimicked by dark pulses, presented during subjective day in constant light (LL). Because behavioral resetting may be mediated in part by 5-HT inputs to the SCN, here we determined whether 5-HT system can modulate dark-induced phase-shifts in Syrian hamsters housed in LL. Two hours of darkness at mid-subjective day (circadian time 6; CT-6) resulted in increased concentrations of 5-HT in the SCN tissue and induction of c-FOS expression in the raphe nuclei. Injections of the 5-HT(1A/7) agonist +8-OH-DPAT or dark pulses at CT-6 induced phase-advances of the wheel-running activity rhythm and down-regulated the expression of the clock genes Per1-2 and c-FOS in the SCN in a similar way. The combination of both treatments [+8-OH-DPAT + dark pulses], however, resulted in larger phase-advances, while associated molecular changes were not significantly modified, except for the gene Dbp, in comparison to +8-OH-DPAT or dark pulses alone. Dark resetting was blocked by pre-treatment with a 5-HT(7) antagonist, but not with a 5-HT(1A) antagonist. The additive phase-shifts of two different cues to reset the SCN clock open wide the gateway for non-photic shifting, leading to new strategies in chronotherapy.
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Affiliation(s)
- Jorge Mendoza
- Institut de Neurosciences Cellulaires et Intégratives, Département de Neurobiologie des Rythmes, CNRS et Université Louis Pasteur, Strasbourg, France.
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138
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Salgado-Delgado R, Angeles-Castellanos M, Buijs MR, Escobar C. Internal desynchronization in a model of night-work by forced activity in rats. Neuroscience 2008; 154:922-31. [PMID: 18472343 DOI: 10.1016/j.neuroscience.2008.03.066] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2007] [Revised: 02/19/2008] [Accepted: 03/25/2008] [Indexed: 11/28/2022]
Abstract
Individuals engaged in shift- or night-work show disturbed diurnal rhythms, out of phase with temporal signals associated to the light/dark (LD) cycle, resulting in internal desynchronization. The mechanisms underlying internal desynchrony have been mainly investigated in experimental animals with protocols that induce phase shifts of the LD cycle and thus modify the activity of the suprachiasmatic nucleus (SCN). In this study we developed an animal model of night-work in which the light-day cycle remained stable and rats were required to be active in a rotating wheel for 8 h daily during their sleeping phase (W-SP). This group was compared with rats that were working in the wheel during their activity phase (W-AP) and with undisturbed rats (C). We provide evidence that forced activity during the sleeping phase (W-SP group) alters not only activity, but also the temporal pattern of food intake. In consequence W-SP rats showed a loss of glucose rhythmicity and a reversed rhythm of triacylglycerols. In contrast W-AP rats did not show such changes and exhibited metabolic rhythms similar to those of the controls. The three groups exhibited the nocturnal corticosterone increase, in addition the W-SP and W-AP groups showed increase of plasma corticosterone associated with the start of the working session. Forced activity during the sleep phase did not modify SCN activity characterized by the temporal patterns of PER1 and PER2 proteins, which remained in phase with the LD cycle. These observations indicate that a working regimen during the sleeping period elicits internal desynchronization in which activity combined with feeding uncouples metabolic functions from the biological clock which remains fixed to the LD cycle. The present data suggest that in the night worker the combination of work and eating during working hours may be the cause of internal desynchronization.
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Affiliation(s)
- R Salgado-Delgado
- Departamento de Anatomía, Facultad de Medicina, Edificio "B" 4 Piso, Universidad Nacional Autónoma de México, México DF 04510, Mexico
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139
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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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140
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Otálora BB, Madrid JA, Alvarez N, Vicente V, Rol MA. Effects of exogenous melatonin and circadian synchronization on tumor progression in melanoma-bearing C57BL6 mice. J Pineal Res 2008; 44:307-15. [PMID: 18339126 DOI: 10.1111/j.1600-079x.2007.00531.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Circadian rhythmicity impairment reportedly becomes significant as a tumor progresses, while the incidence of cancer can be affected by disruption of the circadian system. Melatonin has oncostatic effects on several types of cancer (breast, prostate, and colorectal cancers), while it can be self-defeating in others, such as lymphoma. Melanoma is one of the most aggressive cancers in humans; however, it seems to respond positively to melatonin in vitro. The present work tested whether body temperature (BT) rhythms are impaired by tumor progression, and whether exogenous melatonin restricts tumor growth and restores circadian rhythmicity; therefore, enhancing survival. To this end, C57 mice were intraperitoneal implanted with a temperature data logger and subcutaneously inoculated with melanoma cells. Animals were then submitted to light-dark (LD) 12:12 cycles or continuous light (LL), with or without melatonin administration. Under LD light conditions, the BT rhythm exhibited a marked reduction in the first circadian harmonic amplitude, and increased phase instability (Rayleigh vector) as the tumor progressed. Melatonin administration (2 mg/kg BW/day), on the other hand, increased the BT rhythm amplitude and phase stability, reduced tumor weight and prevented intraperitoneal dissemination. Exposure to LL induced a free-running rhythm (1500 min), significantly increasing tumor malignity, and therefore reducing survival. Surprisingly, the highest tumor weights and morbidity by metastasis were seen in the LL group treated with melatonin probably because this indoleamine was being administered at different subjective hours to free-running animals. Circadian rhythmicity can thus be used as a marker rhythm for tumor progression, as rhythm impairment increases along with tumor malignancy. While melatonin administration improves rhythmicity and enhances survival under LD conditions, the results are self-defeating when they coexist with circadian disruption as it occurs under LL. This emphasizes the importance of taking into account endogenous rhythmicity and limiting melatonin administration to the subjective night in order to restrict melanoma progression.
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Affiliation(s)
- B B Otálora
- Chronobiology Laboratory, Department of Physiology, Faculty of Biology, University of Murcia, Murcia, Spain
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141
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Yi CX, Challet E, Pévet P, Kalsbeek A, Escobar C, Buijs RM. A circulating ghrelin mimetic attenuates light-induced phase delay of mice and light-induced Fos expression in the suprachiasmatic nucleus of rats. Eur J Neurosci 2008; 27:1965-72. [DOI: 10.1111/j.1460-9568.2008.06181.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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142
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Bechtold DA, Brown TM, Luckman SM, Piggins HD. Metabolic rhythm abnormalities in mice lacking VIP-VPAC2 signaling. Am J Physiol Regul Integr Comp Physiol 2008; 294:R344-51. [DOI: 10.1152/ajpregu.00667.2007] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The circadian pacemaker in the suprachiasmatic nuclei (SCN) controls endogenous near 24-h physiological and behavioral rhythms in metabolism, neuroendocrine function, and locomotor activity. Recently, we showed that vasoactive intestinal polypeptide (VIP) and its receptor, VPAC2 are critical to the intercellular communication between individual SCN neurons, and appropriate synchronization and phasing of these oscillatory cells. Mice defective in VIP signaling manifest grossly impaired circadian rhythms of SCN neuronal firing activity and are typically unable to maintain rhythmic wheel-running behavior in the absence of external time cues. Here we report that daily rhythms of metabolism and feeding behavior are also overtly altered in these animals. Under diurnal conditions (12:12-h light-dark; LD), metabolic and feeding rhythms are advanced in mice lacking either VIP or VPAC2 receptor expression, peaking in the late day, rather than early night, as observed in wild-type mice. When placed in constant light (LL), both VIP-deficient and VPAC2 receptor-knockout mice exhibit dampening of metabolic and feeding rhythms, which deteriorate after a few days. In addition, overall metabolic rate is greatly reduced in VPAC2-knockout mice, when compared with wild-type mice, regardless of lighting condition. The advancement of metabolic and feeding rhythms in these mice under LD suggests that these rhythms are less sensitive to masking by light. These results demonstrate that altering SCN function not only affects neuronal and wheel-running activity rhythms but also dramatically impairs temporal regulation of metabolism and feeding.
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143
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Webb IC, Patton DF, Hamson DK, Mistlberger RE. Neural correlates of arousal-induced circadian clock resetting: hypocretin/orexin and the intergeniculate leaflet. Eur J Neurosci 2008; 27:828-35. [DOI: 10.1111/j.1460-9568.2008.06074.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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144
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Mendoza J, Drevet K, Pévet P, Challet E. Daily meal timing is not necessary for resetting the main circadian clock by calorie restriction. J Neuroendocrinol 2008; 20:251-60. [PMID: 18088363 DOI: 10.1111/j.1365-2826.2007.01636.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
In rodents, entrainment and/or resetting by feeding of the central circadian clock, the suprachiasmatic nucleus (SCN), is more efficient when food cues arise from a timed calorie restriction. Because timed calorie restriction is associated with a single meal each day at the same time, its resetting properties on the SCN possibly depend on a combination of meal time-giving cues and hypocaloric conditions per se. To exclude any effect of daily meal timing in resetting by calorie restriction, the present study employed a model of ultradian feeding schedules, divided into six meals with different durations of food access (6 x 8-min versus 6 x 12-min meal schedule) every 4 h over the 24-h cycle. The effects of such an ultradian calorie restriction were evaluated on the rhythms of wheel-running activity (WRA) and body temperature (Tb) in rats. The results indicate that daily/circadian rhythms of WRA and Tb were shifted by a hypocaloric feeding distributed in six ultradian short meals (i.e. 6 x 8-min meal schedule), showing both phase advances and delays. The magnitude of phase shifts was positively correlated with body weight loss and level of day-time behavioural activity. By contrast, rats fed daily with six ultradian meals long enough (i.e. 6 x 12-min meal schedule) to prevent body weight loss, showed only small, if any, phase shifts in WRA and Tb rhythms. The results obtained reveal the potency of calorie restriction to reset the SCN clock without synchronisation to daily meal timing, highlighting functional links between metabolism, calorie restriction and the circadian timing system.
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Affiliation(s)
- J Mendoza
- Institut de Neurosciences Cellulaires et Intégratives, Département de Neurobiologie des Rythmes, UMR7168/LC2, CNRS et Université Louis Pasteur, Strasbourg Cedex, France
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145
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Abstract
Neuromedin S, a novel neuropeptide of 36 amino acids, was isolated from rat brain as an endogenous ligand for the orphan G protein-coupled receptors FM-3/GPR66 and FM-4/TGR-1, identified to date as type-1 and type-2 neuromedin U (NMU) receptors, respectively. The peptide was designated neuromedin S (NMS) because it is specifically expressed in the suprachiasmatic nucleus of the hypothalamus. NMS is structurally related to NMU; these peptides share a C-terminal core structure. In this review, we will outline the recent discoveries regarding the structure, cognate receptors, distribution, and possible physiological functions of NMS.
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146
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Dallmann R, Lemm G, Mrosovsky N. Toward easier methods of studying nonphotic behavioral entrainment in mice. J Biol Rhythms 2008; 22:458-61. [PMID: 17876067 DOI: 10.1177/0748730407306042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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147
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McAllan BM, Westman W, Körtner G, Cairns SC. Sex, season and melatonin administration affects daily activity rhythms in a marsupial, the brown antechinus, Antechinus stuartii. Physiol Behav 2008; 93:130-8. [PMID: 17884113 DOI: 10.1016/j.physbeh.2007.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Revised: 07/30/2007] [Accepted: 08/09/2007] [Indexed: 10/22/2022]
Abstract
The carnivorous marsupial Antechinus stuartii relies on photoperiodic changes to time reproductive activities, including behaviour, in spring. Similar to other mammals, the administration of the hormone melatonin is known to affect the synchronisation of reproduction in A. stuartii. The present study sought to explore the alterations in locomotor activity from the winter solstice in both males (body mass 35 g) and females (body mass 20 g) as a result of the influences of the changes in the natural photocycle and also of melatonin administration while under the natural photocycle. The total daily activity was found to differ between sexes, with males more active than females, irrespective of melatonin or control treatments. Daily activity patterns were significantly different between male groups but not female treatment groups. Activity patterns were also found to differ between males and females. The significance of these differences is discussed with relation to the profound physiological differences between the sexes, in this mammal where an irreversible stress response is part of the complete post-mating mortality of all males, but not females.
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Affiliation(s)
- B M McAllan
- Centre for Behavioural and Physiological Ecology and Discipline of Zoology, University of New England, Armidale, NSW, 2351 Australia.
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148
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Valentinuzzi VS, Diniz GP, Menna-Barreto L, Xavier GF. The experience in the water maze task can affect the circadian rhythm of locomotor activity. BIOL RHYTHM RES 2007. [DOI: 10.1080/09291010601044165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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149
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Karatsoreos IN, Silver R. Minireview: The neuroendocrinology of the suprachiasmatic nucleus as a conductor of body time in mammals. Endocrinology 2007; 148:5640-7. [PMID: 17901227 PMCID: PMC3423957 DOI: 10.1210/en.2007-1083] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Circadian rhythms in physiology and behavior are regulated by a master clock resident in the suprachiasmatic nucleus (SCN) of the hypothalamus, and dysfunctions in the circadian system can lead to serious health effects. This paper reviews the organization of the SCN as the brain clock, how it regulates gonadal hormone secretion, and how androgens modulate aspects of circadian behavior known to be regulated by the SCN. We show that androgen receptors are restricted to a core SCN region that receives photic input as well as afferents from arousal systems in the brain. We suggest that androgens modulate circadian behavior directly via actions on the SCN and that both androgens and estrogens modulate circadian rhythms through an indirect route, by affecting overall activity and arousal levels. Thus, this system has multiple levels of regulation; the SCN regulates circadian rhythms in gonadal hormone secretion, and hormones feed back to influence SCN functions.
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Affiliation(s)
- Ilia N Karatsoreos
- Department of Psychology, Columbia University, 406 Schermerhorn Hall, 1190 Amsterdam Avenue, New York, NY 10027, USA
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150
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Carbachol injections into the intergeniculate leaflet induce nonphotic phase shifts. Brain Res 2007; 1177:59-65. [DOI: 10.1016/j.brainres.2007.07.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Revised: 07/12/2007] [Accepted: 07/31/2007] [Indexed: 12/29/2022]
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