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El Allali K, Beniaich Y, Farsi H, M′hani MEM, Jabal MS, Piro M, Achaâban MR, Ouassat M, Challet E, Besson M, Mounach J, Pévet P, Satté A. Sleep pattern in the dromedary camel: a behavioral and polysomnography study. Sleep 2022; 45:6580315. [DOI: 10.1093/sleep/zsac101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 04/16/2022] [Indexed: 11/14/2022] Open
Abstract
Abstract
Study Objectives
To investigate sleep patterns in the camel by combining behavioral and polysomnography (PSG) methods.
Methods
A noninvasive PSG study was conducted over four nights on four animals. Additionally, video recordings were used to monitor the sleep behaviors associated with different vigilance states.
Results
During the night, short periods of sporadic sleep-like behavior corresponding to a specific posture, sternal recumbency (SR) with the head lying down on the ground, were observed. The PSG results showed rapid shifts between five vigilance states, including wakefulness, drowsiness, rapid eye movement (REM) sleep, non-REM (NREM) sleep, and rumination. The camels typically slept only 1.7 hours per night, subdivided into 0.5 hours of REM sleep and 1.2 hours of NREM sleep. Camels spent most of the night being awake (2.3 hours), ruminating (2.4 hours), or drowsing (1.9 hours). Various combinations of transitions between the different vigilance states were observed, with a notable transition into REM sleep directly from drowsiness (9%) or wakefulness (4%). Behavioral postures were found to correlate with PSG vigilance states, thereby allowing a reliable prediction of the sleep stage based on SR and the head position (erected, motionless, or lying down on the ground). Notably, 100% of REM sleep occurred during the Head Lying Down-SR posture.
Conclusions
The camel is a diurnal species with a polyphasic sleep pattern at night. The best correlation between PSG and ethogram data indicates that sleep duration can be predicted by the behavioral method, provided that drowsiness is considered a part of sleep.
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Affiliation(s)
- Khalid El Allali
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute , Rabat , Morocco
| | - Younes Beniaich
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute , Rabat , Morocco
| | - Hicham Farsi
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute , Rabat , Morocco
| | - Mohammed El Mehdi M′hani
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute , Rabat , Morocco
| | - Mohamed Sobhi Jabal
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute , Rabat , Morocco
| | - Mohammed Piro
- Medicine and Surgical Unit of Domestic Animals, Department of Medicine, Surgery and Reproduction, Hassan II Agronomy and Veterinary Medicine Institute , Rabat , Morocco
| | - Mohamed Rachid Achaâban
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute , Rabat , Morocco
| | - Mohammed Ouassat
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute , Rabat , Morocco
| | - Etienne Challet
- Institute of Cellular and Integrative Neurosciences, CNRS and University of Strasbourg , Strasbourg , France
| | - Mireille Besson
- Cognitive Neurosciences Laboratory, CNRS and Aix-Marseille University , Marseille , France
| | - Jamal Mounach
- Department of Neurophysiology, Military Hospital Mohammed V , Rabat , Morocco
| | - Paul Pévet
- Institute of Cellular and Integrative Neurosciences, CNRS and University of Strasbourg , Strasbourg , France
| | - Amal Satté
- Department of Neurophysiology, Military Hospital Mohammed V , Rabat , Morocco
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Gao D, Zhao H, Dong H, Li Y, Zhang J, Zhang H, Zhang Y, Jiang H, Wang X, Wang A, Jin Y, Chen H. Transcriptional Feedback Loops in the Caprine Circadian Clock System. Front Vet Sci 2022; 9:814562. [PMID: 35478603 PMCID: PMC9035992 DOI: 10.3389/fvets.2022.814562] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 03/18/2022] [Indexed: 12/25/2022] Open
Abstract
The circadian clock system is based on interlocked positive and negative transcriptional and translational feedback loops of core clock genes and their encoded proteins. The mammalian circadian clock system has been extensively investigated using mouse models, but has been poorly investigated in diurnal ruminants. In this study, goat embryonic fibroblasts (GEFs) were isolated and used as a cell model to elucidate the caprine circadian clock system. Real-time quantitative PCR analysis showed that several clock genes and clock-controlled genes were rhythmically expressed in GEFs over a 24 h period after dexamethasone stimulation. Immunofluorescence revealed that gBMAL1 and gNR1D1 proteins were expressed in GEFs, and western blotting analysis further verified that the proteins were expressed with circadian rhythmic changes. Diurnal changes in clock and clock-controlled gene expression at the mRNA and protein levels were also observed in goat liver and kidney tissues at two representative time points in vivo. Amino acid sequences and tertiary structures of goat BMAL1 and CLOCK proteins were found to be highly homologous to those in mice and humans. In addition, a set of goat representative clock gene orthologs and the promoter regions of two clock genes of goats and mice were cloned. Dual-luciferase reporter assays showed that gRORα could activate the promoter activity of the goat BMAL1, while gNR1D1 repressed it. The elevated pGL4.10-gNR1D1-Promoter-driven luciferase activity induced by mBMAL1/mCLOCK was much higher than that induced by gBMAL1/gCLOCK, and the addition of gCRY2 or mPER2 repressed it. Real-time bioluminescence assays revealed that the transcriptional activity of BMAL1 and NR1D1 in goats and mice exhibited rhythmic changes over a period of approximately 24 h in NIH3T3 cells or GEFs. Notably, the amplitudes of gBMAL1 and gNR1D1 promoter-driven luciferase oscillations in NIH3T3 cells were higher than those in GEFs, while mBMAL1 and mNR1D1 promoter-driven luciferase oscillations in NIH3T3 cells had the highest amplitude. In sum, transcriptional and translational loops of the mammalian circadian clock system were found to be broadly conserved in goats and not as robust as those found in mice, at least in the current experimental models. Further studies are warranted to elucidate the specific molecular mechanisms involved.
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Affiliation(s)
- Dengke Gao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Hongcong Zhao
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Hao Dong
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Yating Li
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Jing Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Haisen Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Yu Zhang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Haizhen Jiang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Xiaoyu Wang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Aihua Wang
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Yaping Jin
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
| | - Huatao Chen
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- Key Laboratory of Animal Biotechnology of the Ministry of Agriculture and Rural Affairs, College of Veterinary Medicine, Northwest A&F University, Xianyang, China
- *Correspondence: Huatao Chen
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Entrainment of circadian rhythms of locomotor activity by ambient temperature cycles in the dromedary camel. Sci Rep 2020; 10:19515. [PMID: 33177571 PMCID: PMC7658228 DOI: 10.1038/s41598-020-76535-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 10/29/2020] [Indexed: 11/08/2022] Open
Abstract
In the dromedary camel, a well-adapted desert mammal, daily ambient temperature (Ta)-cycles have been shown to synchronize the central circadian clock. Such entrainment has been demonstrated by examining two circadian outputs, body temperature and melatonin rhythms. Locomotor activity (LA), another circadian output not yet investigated in the camel, may provide further information on such specific entrainment. To verify if daily LA is an endogenous rhythm and whether the desert Ta-cycle can entrain it, six dromedaries were first kept under total darkness and constant-Ta. Results showed that the LA rhythm free runs with a period of 24.8–24.9 h. After having verified that the light–dark cycle synchronizes LA, camels were subjected to a Ta-cycle with warmer temperatures during subjective days and cooler temperatures during subjective nights. Results showed that the free-running LA rhythm was entrained by the Ta-cycle with a period of exactly 24.0 h, while a 12 h Ta-cycle phase advance induced an inversion of the LA rhythm and advanced the acrophase by 9 h. Similarly, activity onset and offset were significantly advanced. All together, these results demonstrate that the Ta-cycle is a strong zeitgeber, able to entrain the camel LA rhythm, hence corroborating previous results concerning the Ta non-photic synchronization of the circadian master clock.
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Farsi H, Harti D, Achaâban MR, Piro M, Raverot V, Bothorel B, Ouassat M, Challet E, Pévet P, El Allali K. Melatonin rhythm and other outputs of the master circadian clock in the desert goat (Capra hircus) are entrained by daily cycles of ambient temperature. J Pineal Res 2020; 68:e12634. [PMID: 32011000 DOI: 10.1111/jpi.12634] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/20/2020] [Accepted: 01/22/2020] [Indexed: 02/03/2023]
Abstract
In desert areas, mammals such as camel and goat are exposed to harsh environmental conditions. The ambient temperature (Ta) cycles have been shown to entrain the circadian clock in the camel. In the present work, we assumed that, in the goat living in a desert biotope, Ta cycles would have the same synchronizing effect on the central clock. Therefore, the effects of Ta cycles on body temperature (Tb), locomotor activity (LA) and melatonin (Mel) rhythms as outputs of the master circadian clock have been studied. The study was performed on bucks kept first under constant conditions of total darkness (DD) and constant Ta, then maintained under DD conditions but exposed to Ta cycles with heat period during subjective day and cold period during subjective night. Finally, the Ta cycles were reversed with highest temperatures during the subjective night and the lowest temperatures during the subjective day. Under constant conditions, the circadian rhythms of Tb and LA were free running with an endogenous period of 25.3 and 25.0 hours, respectively. Ta cycles entrained the rhythms of Tb and LA to a period of exactly 24.0 hours; while when reversed, the Ta cycles led to an inversion of Tb and LA rhythms. Similarly, Ta cycles were also able to entrain Mel rhythm, by adjusting its secretion to the cooling phase before and after Ta cycles inversion. All together, these results show that the Ta cycles entrain the master circadian clock in the goat.
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Affiliation(s)
- Hicham Farsi
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute, Rabat, Morocco
| | - Driss Harti
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute, Rabat, Morocco
| | - Mohamed R Achaâban
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute, Rabat, Morocco
| | - Mohammed Piro
- Medicine and Surgical Unit of domestic animals, Department of Medicine, Surgery and reproduction, Hassan II Agronomy and Veterinary Medicine Institute, Rabat, Morocco
| | - Véronique Raverot
- Laboratory of Hormonology, East Center for Biology and Pathology, East Hospital Group, Civil Hospices of Lyon, Lyon, France
| | - Béatrice Bothorel
- Institute of Cellular and Integrative Neurosciences, CNRS and University of Strasbourg, Strasbourg, France
| | - Mohammed Ouassat
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute, Rabat, Morocco
| | - Etienne Challet
- Institute of Cellular and Integrative Neurosciences, CNRS and University of Strasbourg, Strasbourg, France
| | - Paul Pévet
- Institute of Cellular and Integrative Neurosciences, CNRS and University of Strasbourg, Strasbourg, France
| | - Khalid El Allali
- Comparative Anatomy Unit, Department of Biological and Pharmaceutical Veterinary Sciences, Hassan II Agronomy and Veterinary Medicine Institute, Rabat, Morocco
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