1
|
Shi Z, Qin M, Huang L, Xu T, Chen Y, Hu Q, Peng S, Peng Z, Qu LN, Chen SG, Tuo QH, Liao DF, Wang XP, Wu RR, Yuan TF, Li YH, Liu XM. Human torpor: translating insights from nature into manned deep space expedition. Biol Rev Camb Philos Soc 2020; 96:642-672. [PMID: 33314677 DOI: 10.1111/brv.12671] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 11/09/2020] [Accepted: 11/17/2020] [Indexed: 12/12/2022]
Abstract
During a long-duration manned spaceflight mission, such as flying to Mars and beyond, all crew members will spend a long period in an independent spacecraft with closed-loop bioregenerative life-support systems. Saving resources and reducing medical risks, particularly in mental heath, are key technology gaps hampering human expedition into deep space. In the 1960s, several scientists proposed that an induced state of suppressed metabolism in humans, which mimics 'hibernation', could be an ideal solution to cope with many issues during spaceflight. In recent years, with the introduction of specific methods, it is becoming more feasible to induce an artificial hibernation-like state (synthetic torpor) in non-hibernating species. Natural torpor is a fascinating, yet enigmatic, physiological process in which metabolic rate (MR), body core temperature (Tb ) and behavioural activity are reduced to save energy during harsh seasonal conditions. It employs a complex central neural network to orchestrate a homeostatic state of hypometabolism, hypothermia and hypoactivity in response to environmental challenges. The anatomical and functional connections within the central nervous system (CNS) lie at the heart of controlling synthetic torpor. Although progress has been made, the precise mechanisms underlying the active regulation of the torpor-arousal transition, and their profound influence on neural function and behaviour, which are critical concerns for safe and reversible human torpor, remain poorly understood. In this review, we place particular emphasis on elaborating the central nervous mechanism orchestrating the torpor-arousal transition in both non-flying hibernating mammals and non-hibernating species, and aim to provide translational insights into long-duration manned spaceflight. In addition, identifying difficulties and challenges ahead will underscore important concerns in engineering synthetic torpor in humans. We believe that synthetic torpor may not be the only option for manned long-duration spaceflight, but it is the most achievable solution in the foreseeable future. Translating the available knowledge from natural torpor research will not only benefit manned spaceflight, but also many clinical settings attempting to manipulate energy metabolism and neurobehavioural functions.
Collapse
Affiliation(s)
- Zhe Shi
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China.,Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China
| | - Meng Qin
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Lu Huang
- Guangdong-Hongkong-Macau Institute of CNS Regeneration, Ministry of Education CNS Regeneration Collaborative Joint Laboratory, Jinan University, Guangzhou, 510632, China
| | - Tao Xu
- Department of Anesthesiology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, China
| | - Ying Chen
- Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China
| | - Qin Hu
- College of Life Sciences and Bio-Engineering, Beijing University of Technology, Beijing, 100024, China
| | - Sha Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Zhuang Peng
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Li-Na Qu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Shan-Guang Chen
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Qin-Hui Tuo
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Duan-Fang Liao
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China
| | - Xiao-Ping Wang
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ren-Rong Wu
- National Clinical Research Center for Mental Disorders, and Department of Psychaitry, The Second Xiangya Hospital of Central South University, Changsha, Hunan, 410011, China
| | - Ti-Fei Yuan
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiaotong University School of Medicine, Shanghai, 200030, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, 226000, China
| | - Ying-Hui Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Xin-Min Liu
- Key Laboratory for Quality Evaluation of Bulk Herbs of Hunan Province, Hunan University of Chinese Medicine, Changsha, Hunan, 410208, China.,State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China.,Research Center for Pharmacology and Toxicology, Institute of Medicinal Plant Development (IMPLAD), Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100193, China
| |
Collapse
|
2
|
Sonntag M, Arendt T. Neuronal Activity in the Hibernating Brain. Front Neuroanat 2019; 13:71. [PMID: 31338028 PMCID: PMC6629779 DOI: 10.3389/fnana.2019.00071] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 06/26/2019] [Indexed: 11/13/2022] Open
Abstract
Hibernation is a natural phenomenon in many species which helps them to survive under extreme ambient conditions, such as cold temperatures and reduced availability of food in the winter months. It is characterized by a dramatic and regulated drop of body temperature, which in some cases can be near 0°C. Additionally, neural control of hibernation is maintained over all phases of a hibernation bout, including entrance into, during and arousal from torpor, despite a marked decrease in overall neural activity in torpor. In the present review, we provide an overview on what we know about neuronal activity in the hibernating brain focusing on cold-induced adaptations. We discuss pioneer and more recent in vitro and in vivo electrophysiological data and molecular analyses of activity markers which strikingly contributed to our understanding of the brain's sensitivity to dramatic changes in temperature across the hibernation cycle. Neuronal activity is markedly reduced with decreasing body temperature, and many neurons may fire infrequently in torpor at low brain temperatures. Still, there is convincing evidence that specific regions maintain their ability to generate action potentials in deep torpor, at least in response to adequate stimuli. Those regions include the peripheral system and primary central regions. However, further experiments on neuronal activity are needed to more precisely determine temperature effects on neuronal activity in specific cell types and specific brain nuclei.
Collapse
Affiliation(s)
- Mandy Sonntag
- Paul-Flechsig-Institute of Brain Research, Medical Faculty, University of Leipzig, Leipzig, Germany
| | - Thomas Arendt
- Paul-Flechsig-Institute of Brain Research, Medical Faculty, University of Leipzig, Leipzig, Germany
| |
Collapse
|
3
|
Angilletta MJ, Youngblood JP, Neel LK, VandenBrooks JM. The neuroscience of adaptive thermoregulation. Neurosci Lett 2019; 692:127-136. [DOI: 10.1016/j.neulet.2018.10.046] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/17/2018] [Accepted: 10/21/2018] [Indexed: 01/05/2023]
|
4
|
Saitongdee P, Becker DL, Milner P, Knight GE, Burnstock G. Levels of Gap Junction Proteins in Coronary Arterioles and Aorta of Hamsters Exposed to the Cold and During Hibernation and Arousal. J Histochem Cytochem 2016; 52:603-15. [PMID: 15100238 DOI: 10.1177/002215540405200505] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
There are marked changes in vascular dynamics during prolonged periods in the cold, entrance into hibernation, and arousal to euthermy. Cell-to-cell communication through gap junction channels plays a pivotal role in the control of vasomotor function. Multiple gap junction proteins are expressed in blood vessels, including connexins 37 (Cx37), 40 (Cx40), 43 (Cx43), and 45 (Cx45). Using immunolabeling techniques combined with confocal microscopy, we quantitated the levels of these connexins in coronary arterioles and the thoracic aorta of the golden hamster in four physiological conditions: normal control animals at euthermy; cold-exposed animals (before entrance into hibernation); during hibernation; and after 2-hr arousal from hibernation. In all groups, Cx37 was localized between endothelial cells of the aorta and Cx40 was observed between endothelial cells of coronary arterioles and the aorta. Cx43 was confined to smooth muscle cells of the aorta. Labeling for Cx45 was detected in the endothelium of the ascending aorta. The expression of Cx37 was significantly reduced in cold-exposed, hibernating, and aroused animals. Immunolabeling for Cx40 was increased in the coronary arteriolar endothelium of the cold-exposed group compared with normal controls, hibernating, and aroused animals, perhaps to facilitate intercellular communication during the prolonged circulatory changes to vascular dynamics required to maintain core temperature during cold adaptation. Cx40 expression was unchanged in the aorta. Cx43 immunoexpression in the aorta remained constant under all conditions examined. These changes in connexin expression did not occur during the rapid circulatory changes associated with arousal from hibernation.
Collapse
|
5
|
Yuan L, Geiser F, Lin B, Sun H, Chen J, Zhang S. Down but Not Out: The Role of MicroRNAs in Hibernating Bats. PLoS One 2015; 10:e0135064. [PMID: 26244645 PMCID: PMC4526555 DOI: 10.1371/journal.pone.0135064] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 07/16/2015] [Indexed: 01/17/2023] Open
Abstract
MicroRNAs (miRNAs) regulate many physiological processes through post-transcriptional control of gene expression and are a major part of the small noncoding RNAs (snRNA). As hibernators can survive at low body temperatures (Tb) for many months without suffering tissue damage, understanding the mechanisms that enable them to do so are of medical interest. Because the brain integrates peripheral physiology and white adipose tissue (WAT) is the primary energy source during hibernation, we hypothesized that both of these organs play a crucial role in hibernation, and thus, their activity would be relatively increased during hibernation. We carried out the first genomic analysis of small RNAs, specifically miRNAs, in the brain and WAT of a hibernating bat (Myotis ricketti) by comparing deeply torpid with euthermic individual bats using high-throughput sequencing (Solexa) and qPCR validation of expression levels. A total of 196 miRNAs (including 77 novel bat-specific miRNAs) were identified, and of these, 49 miRNAs showed significant differences in expression during hibernation, including 33 in the brain and 25 in WAT (P≤0.01 &│logFC│≥1). Stem-loop qPCR confirmed the miRNA expression patterns identified by Solexa sequencing. Moreover, 31 miRNAs showed tissue- or state-specific expression, and six miRNAs with counts >100 were specifically expressed in the brain. Putative target gene prediction combined with KEGG pathway and GO annotation showed that many essential processes of both organs are significantly correlated with differentially expressed miRNAs during bat hibernation. This is especially evident with down-regulated miRNAs, indicating that many physiological pathways are altered during hibernation. Thus, our novel findings of miRNAs and Interspersed Elements in a hibernating bat suggest that brain and WAT are active with respect to the miRNA expression activity during hibernation.
Collapse
Affiliation(s)
- Lihong Yuan
- Guangdong Entomological Institute, Guangzhou, China
- Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Guangzhou, China
- Guangdong Key Laboratory of Integrated Pest Management in Agriculture, Guangzhou, China
| | - Fritz Geiser
- Center for Behavioural and Physiological Ecology, Zoology, University of New England, Armidale, Australia
| | - Benfu Lin
- Animal Husbandry and Veterinary Bureau of Huadu District, Guangzhou, China
| | - Haibo Sun
- MininGene Biotechnology Co. Ltd, Beijing, China
| | - Jinping Chen
- Guangdong Entomological Institute, Guangzhou, China
- Guangdong Public Laboratory of Wild Animal Conservation and Utilization, Guangzhou, China
- Guangdong Key Laboratory of Integrated Pest Management in Agriculture, Guangzhou, China
| | - Shuyi Zhang
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research, East China Normal University, Shanghai, China
| |
Collapse
|
6
|
Lei M, Dong D, Mu S, Pan YH, Zhang S. Comparison of brain transcriptome of the greater horseshoe bats (Rhinolophus ferrumequinum) in active and torpid episodes. PLoS One 2014; 9:e107746. [PMID: 25251558 PMCID: PMC4174523 DOI: 10.1371/journal.pone.0107746] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 08/21/2014] [Indexed: 01/03/2023] Open
Abstract
Hibernation is an energy-saving strategy which is widely adopted by heterothermic mammals to survive in the harsh environment. The greater horseshoe bat (Rhinolophus ferrumequinum) can hibernate for a long period in the hibernation season. However, the global gene expression changes between hibernation and non-hibernation season in the greater horseshoe bat remain largely unknown. We herein reported a comprehensive survey of differential gene expression in the brain between winter hibernating and summer active greater horseshoe bats using next-generation sequencing technology. A total of 90,314,174 reads were generated and we identified 1,573 differentially expressed genes between active and torpid states. Interestingly, we found that differentially expressed genes are over-represented in some GO categories (such as metabolic suppression, cellular stress responses and oxidative stress), which suggests neuroprotective strategies might play an important role in hibernation control mechanisms. Our results determined to what extent the brain tissue of the greater horseshoe bats differ in gene expression between summer active and winter hibernating states and provided comprehensive insights into the adaptive mechanisms of bat hibernation.
Collapse
Affiliation(s)
- Ming Lei
- Institute of Molecular Ecology and Evolution, SKLEC & IECR, East China Normal University, Shanghai, China
| | - Dong Dong
- Institute of Molecular Ecology and Evolution, SKLEC & IECR, East China Normal University, Shanghai, China
- * E-mail: (DD); (SZ)
| | - Shuo Mu
- Institute of Molecular Ecology and Evolution, SKLEC & IECR, East China Normal University, Shanghai, China
| | - Yi-Hsuan Pan
- Institute of Molecular Ecology and Evolution, SKLEC & IECR, East China Normal University, Shanghai, China
| | - Shuyi Zhang
- Institute of Molecular Ecology and Evolution, SKLEC & IECR, East China Normal University, Shanghai, China
- * E-mail: (DD); (SZ)
| |
Collapse
|
7
|
Zhu T, Yuan L, Jones G, Hua P, He G, Chen J, Zhang S. OB-RL silencing inhibits the thermoregulatory ability of Great Roundleaf Bats (Hipposideros armiger). Gen Comp Endocrinol 2014; 204:80-7. [PMID: 24815886 DOI: 10.1016/j.ygcen.2014.04.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 04/22/2014] [Accepted: 04/26/2014] [Indexed: 10/25/2022]
Abstract
Previous studies have shown that the hormone Leptin has an important role in mammalian heterothermy by regulating metabolism and food intake via lipolysis, as well as adaptive evolution of Leptin in heterothermic bats driven by selected pressure. However, the mechanism of Leptin in heterothermic regulation in mammals is unknown. By combining previous results, we speculated that the Leptin signaling pathway mediated by OB-RL (Leptin receptor long form) in the hypothalamus is important. OB-RL is one of the products of db gene and mainly distributed in the hypothalamus. In this study, we used OB-RL as a molecular marker, combining with the RNA interference technology and physiological/molecular analyses with Hipposideros armiger (a hibernating bat species) as an animal model, to explore the mechanism of Leptin in heterothermic regulation. Our data showed that all of four anti-OB-RL shRNA lentivirus significantly inhibited OB-RL expression (>90%), and the interference efficiency of PSC1742 lentivirus reached the highest value. In situ hybridization proved that PSC1742 lentivirus significantly decreased the OB-RL expression in the hypothalamus, especially in the ventromedial hypothalamic nucleus (VHM, 86.6%). Physiological analysis demonstrated that the thermoregulatory ability of bats (e.g., reducing core body temperature and heart rate) was significantly depressed after OB-RL silencing in the hypothalamus, and animals could not enter torpor state. Our study for the first time proved that the knock-down of OB-RL expression in hypothalamus inhibits heterothermic regulation of bats, and also provided the clues for further analyzing the mechanism of Leptin in the heterothermic regulation of mammals.
Collapse
Affiliation(s)
- Tengteng Zhu
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research in Science and Technology, East China Normal University, Shanghai 200062, China
| | - Lihong Yuan
- Guangdong Entomological Institute/South China Institute of Endangered Animals, Guangzhou 510260, China.
| | - Gareth Jones
- School of Biological Sciences, University of Bristol, Woodland Road, BS8 1UG Bristol, United Kingdom
| | - Panyu Hua
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research in Science and Technology, East China Normal University, Shanghai 200062, China
| | - Guimei He
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research in Science and Technology, East China Normal University, Shanghai 200062, China
| | - Jinping Chen
- Guangdong Entomological Institute/South China Institute of Endangered Animals, Guangzhou 510260, China
| | - Shuyi Zhang
- Institute of Molecular Ecology and Evolution, Institutes for Advanced Interdisciplinary Research in Science and Technology, East China Normal University, Shanghai 200062, China.
| |
Collapse
|
8
|
Seasonal and sex differences in the hippocampus of a wild rodent. Behav Brain Res 2012; 236:131-138. [PMID: 22974551 DOI: 10.1016/j.bbr.2012.08.044] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 07/29/2012] [Accepted: 08/28/2012] [Indexed: 01/14/2023]
Abstract
Studies across and within species suggest that hippocampus size is sexually dimorphic in polygamous species, but not in monogamous species. Although hippocampal volume varies with sex, season and mating system, few studies have simultaneously tested for sex and seasonal differences. Here, we test for sex and seasonal differences in the hippocampal volume of wild Richardson's ground squirrels (Urocitellus richardsonii), a polygamous species that lives in matrilineal, kin-based social groups and has profound sex differences in behavior. Based on the behavior and ecology of this species, we predicted that males would have a significantly larger hippocampus than females and that the hippocampus would be largest in males during the breeding season. Analyses of both absolute and relative volumes of the hippocampus yielded a significant difference between the sexes and seasons as well as an interaction between the two such that non-breeding males have significantly larger hippocampal volumes than breeding males or females from either season. Dentate gyrus, CA1 and CA3 subfield volumes were generally larger in the non-breeding season and in males, but no significant interaction effects were detected. This sex and seasonal variation in hippocampal volume is likely the result of their social organization and male-only food caching behavior during the non-breeding season. The demonstration of a sex and seasonal variation in hippocampal volume suggests that Richardson's ground squirrel may be a useful model for understanding hippocampal plasticity within a natural context.
Collapse
|
9
|
Matching cellular metabolic supply and demand in energy-stressed animals. Comp Biochem Physiol A Mol Integr Physiol 2009; 153:95-105. [PMID: 19535026 DOI: 10.1016/j.cbpa.2009.02.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 01/30/2009] [Accepted: 02/02/2009] [Indexed: 12/31/2022]
Abstract
Certain environmental stressors can impair cellular ATP production to the point of harming or even killing an animal. Some exceptional animals employ strategies that maintain the balance between ATP production and consumption, allowing them to tolerate prolonged exposure to stressors such as hypoxia and anoxia. Anoxia- and hypoxia-tolerant animals reduce ATP consumption by ion-motive ATPases while concomitant reductions in passive ion flux reduce the demand for ion pumping and maintain transmembrane ion gradients. Reductions in gene transcription and protein turnover decrease ATP demand in hibernating and hypoxia-tolerant animals. Proton leak uncouples mitochondrial substrate oxidation from ATP synthesis and accounts for a considerable proportion of cellular energy demand, but there is little evidence that the proton permeability of inner mitochondrial membranes decreases in animals that tolerate energy stress. Indeed in some cases proton leak increases, possibly reducing reactive oxygen species production. Because substrate oxidation is important to the control of cellular metabolism, the downregulation of ATP supply pathways contributes significantly to metabolic suppression under energy stress. Mechanisms that coordinate the downregulation of both ATP supply and demand pathways include AMP kinase and ATP-sensitive ion channels. Strategies employed by animals tolerant to one energy stress often convey "cross-tolerance" to completely different stresses.
Collapse
|
10
|
Nathaniel TI. Brain-regulated metabolic suppression during hibernation: a neuroprotective mechanism for perinatal hypoxia-ischemia. Int J Stroke 2008; 3:98-104. [PMID: 18706003 DOI: 10.1111/j.1747-4949.2008.00186.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hypoxic-ischemic brain injury in the perinatal period is a major cause of chronic disability and acute mortality in newborns. Despite numerous therapeutic strategies that reduce hypoxia-ischemia-induced damage in different experimental animal models, most of them have failed to translate to clinical therapies. This challenge calls for an urgent need to explore novel approaches to develop effective therapies for the clinical management of perinatal hypoxia-ischemia brain injury. This review focuses on studies that investigate neuroprotective related events during mammalian hibernation, characterized by dramatic reductions in several parameters including body temperature, oxygen consumption and heart rate, such that it is difficult to tell if the hibernating animal is dead or alive. The first part of this article reviews the mechanisms of metabolic suppression related events during hibernation. In the second part, hypoxic-ischemic events in the perinatal brain are discussed, and in turn, contrasted with brains experiencing metabolic suppression during mammalian hibernation. In the last part of this article, the diverse neuroprotective adaptations of hibernators and the mechanisms that might be involved in mammalian hibernation, and how they could in turn, contribute to neurprotection during perinatal hypoxia-ischemia related injuries are discussed. This article appraises the novel idea that knowledge of the central mechanisms involved in the regulatory metabolic suppression, during which; hibernators switch themselves off without dissolving their brains could represent brain neuroprotective strategy for the clinical management of perinatal hypoxia-ischemia brain injuries in newborns.
Collapse
Affiliation(s)
- Thomas I Nathaniel
- Center for Natural and Health Sciences, Marywood University, 2300 Adams Avenue, Scranton, PA 18509, USA.
| |
Collapse
|
11
|
Changes of characteristics of preoptic neurons and NA metabolism in hypothalamus of ground squirrel (Citelleus Dautieus) in different seasons and hibernating phases. SCIENCE IN CHINA. SERIES C, LIFE SCIENCES 2008; 41:488-97. [PMID: 18726230 DOI: 10.1007/bf02882886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/1998] [Indexed: 10/22/2022]
Abstract
The unit firing activities of neurons in the preoptic area (POA) of ground squirrel hypothalamic tissue slices were recorded and the metabolism of NA in hypothalamus was measured with high performance liquid chromatography (HPLC). Thermosensitivity, proportions, the critical temperature (Tc) and the lowest temperature (TL) of firing activity of the above-mentioned neurons, and NA metabolism in hypothalamus were compared in different seasons and hibernating phases. In comparison with that in summer euthermar, it was shown that (i) the percentage and thermosensitivity of the POA neurons varied respectively in the hibernating phases; (ii) TL and Tc of the POA neurons in winter, both euthermar and hibernation, were markedly decreased; (iii) the POA neurons in hibernation became much more sensitive to NA, and the response of cold-sensitive neurons to NA changed from inhibiting pattern in summer to exciting one in hibernation; (iv) the contents and metabolism of NA in hypothalamus decreased significantly in the entering phase and deep hibernation phase, while the metabolism of NA increased remarkably in the arousal phase. These changes might explain the regulatory mechanism how ground squirrel actively decreases body temperature (Tb) in entering into hibernation and quickly recovers body temperature in arousal phase.
Collapse
|
12
|
Yuan L, Chen J, Lin B, Zhang J, Zhang S. Differential expression and functional constraint of PRL-2 in hibernating bat. Comp Biochem Physiol B Biochem Mol Biol 2007; 148:375-81. [PMID: 17683965 DOI: 10.1016/j.cbpb.2007.07.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2007] [Revised: 07/07/2007] [Accepted: 07/07/2007] [Indexed: 11/21/2022]
Abstract
Circannual hibernation is a biological adaptation to periods of cold and food shortage and the role of the brain in its control is poorly understood. An SSH library of hibernating bat brains (Rhinolophus ferrumequinum) was constructed in order to explore the molecular mechanism of hibernation. An up-regulated gene, PRL-2, was obtained from hibernating bat brains. PRL-2 is a member of PTP family and has an important function in controlling cell growth. Alignment of sequences showed that PRL-2 is highly conserved among species, including two species of hibernating bats (R. ferrumequinum and Myotis ricketti). Moreover, Maximum Likelihood Analysis suggested that it may experience strong selection pressure leading to functional constraint in evolution, which indicated the significance of PRL-2 in normal bio-function. RQ-PCR was performed and statistical analysis suggested that PRL-2 exhibited distinct differential expression patterns in different organs during hibernation. In heart, fat and brain tissue of hibernating bats, the transcriptional level of PRL-2 increased almost 170%, 35% and 12% respectively. However, in muscle it decreased nearly 70%. The change of mRNA level of PRL-2 in heart tissue of hibernating bats was significantly higher than that in heart tissue of active controls (P=0.043). However, the regulation mechanism of differential expression of PRL-2 and the signal pathway involved are still unknown.
Collapse
Affiliation(s)
- Lihong Yuan
- School of Life Science, East China Normal University, Shanghai 200062, China
| | | | | | | | | |
Collapse
|
13
|
Chen J, Yuan L, Sun M, Zhang L, Zhang S. Screening of hibernation-related genes in the brain of Rhinolophus ferrumequinum during hibernation. Comp Biochem Physiol B Biochem Mol Biol 2007; 149:388-93. [PMID: 18055242 DOI: 10.1016/j.cbpb.2007.10.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2007] [Revised: 10/29/2007] [Accepted: 10/29/2007] [Indexed: 01/17/2023]
Abstract
The greater horseshoe bat (Rhinolophus ferrumequinum) is a widely distributed small mammal that hibernates annually. A systematic study was initiated to identify differentially expressed genes in hibernating and aroused states of the greater horseshoe bat brain by using suppressed subtractive hybridization technique and dot blot. Forty-one over-expressed ESTs in the hibernating state were found and 17 were known genes reported in NCBI. Among these 17 genes, three were further checked by real time PCR. The bioinformatics analysis suggests that the major over-expressed ESTs may be responsible for the regulation of cell cycle and apoptosis, the growth of neurons, signal transduction and neuroprotection, gene expression regulation, and intracellular trafficking.
Collapse
Affiliation(s)
- Jinping Chen
- South China Institute of Endangered Animals, Guangzhou, 510260, China
| | | | | | | | | |
Collapse
|
14
|
Drew KL, Buck CL, Barnes BM, Christian SL, Rasley BT, Harris MB. Central nervous system regulation of mammalian hibernation: implications for metabolic suppression and ischemia tolerance. J Neurochem 2007; 102:1713-1726. [PMID: 17555547 PMCID: PMC3600610 DOI: 10.1111/j.1471-4159.2007.04675.x] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Torpor during hibernation defines the nadir of mammalian metabolism where whole animal rates of metabolism are decreased to as low as 2% of basal metabolic rate. This capacity to decrease profoundly the metabolic demand of organs and tissues has the potential to translate into novel therapies for the treatment of ischemia associated with stroke, cardiac arrest or trauma where delivery of oxygen and nutrients fails to meet demand. If metabolic demand could be arrested in a regulated way, cell and tissue injury could be attenuated. Metabolic suppression achieved during hibernation is regulated, in part, by the central nervous system through indirect and possibly direct means. In this study, we review recent evidence for mechanisms of central nervous system control of torpor in hibernating rodents including evidence of a permissive, hibernation protein complex, a role for A1 adenosine receptors, mu opiate receptors, glutamate and thyrotropin-releasing hormone. Central sites for regulation of torpor include the hippocampus, hypothalamus and nuclei of the autonomic nervous system. In addition, we discuss evidence that hibernation phenotypes can be translated to non-hibernating species by H(2)S and 3-iodothyronamine with the caveat that the hypothermia, bradycardia, and metabolic suppression induced by these compounds may or may not be identical to mechanisms employed in true hibernation.
Collapse
Affiliation(s)
- Kelly L. Drew
- Institute of Arctic Biology, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - C. Loren Buck
- Department of Biological Sciences, University of Alaska Anchorage, Anchorage, Alaska, USA
| | - Brian M. Barnes
- Institute of Arctic Biology, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Sherri L. Christian
- Institute of Arctic Biology, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Brian T. Rasley
- Department of Chemistry and Biochemistry, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| | - Michael B. Harris
- Institute of Arctic Biology, Alaska Basic Neuroscience Program, University of Alaska Fairbanks, Fairbanks, Alaska, USA
| |
Collapse
|
15
|
Abstract
All mammals and birds must develop effective strategies to cope with reduced oxygen availability. These animals achieve tolerance to acute and chronic hypoxia by (a) reductions in metabolism, (b) the prevention of cellular injury, and (c) the maintenance of functional integrity. Failure to meet any one of these tasks is detrimental. Birds and mammals accomplish this triple task through a highly coordinated, systems-level reconfiguration involving the partial shutdown of some but not all organs. This reconfiguration is achieved through a similarly complex reconfiguration at the cellular and molecular levels. Reconfiguration at these various levels depends on numerous factors that include the environment, the degree of hypoxic stress, and developmental, behavioral, and ecological conditions. Although common molecular strategies exist, the cellular and molecular changes in any given cell are very diverse. Some cells remain metabolically active, whereas others shut down or rely on anaerobic metabolism. This cellular shutdown is temporarily regulated, and during hypoxic exposure, active cellular networks must continue to control vital functions. The challenge for future research is to explore the cellular mechanisms and conditions that transform an organ or a cellular network into a hypometabolic state, without loss of functional integrity. Much can be learned in this respect from nature: Diving, burrowing, and hibernating animals living in diverse environments are masters of adaptation and can teach us how to deal with hypoxia, an issue of great clinical significance.
Collapse
Affiliation(s)
- Jan-Marino Ramirez
- Department of Organismal Biology & Anatomy, University of Chicago, Chicago, Illinois 60637, USA.
| | | | | |
Collapse
|
16
|
Magariños AM, McEwen BS, Saboureau M, Pevet P. Rapid and reversible changes in intrahippocampal connectivity during the course of hibernation in European hamsters. Proc Natl Acad Sci U S A 2006; 103:18775-80. [PMID: 17121986 PMCID: PMC1693738 DOI: 10.1073/pnas.0608785103] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The hippocampal formation is a highly plastic brain structure that undergoes structural remodeling in response to internal and external challenges such as metabolic imbalance and repeated stress. We investigated whether the extreme alterations in metabolic status that occur during the course of hibernation in European hamsters cause structural changes in the dendritic arborizations of the CA3 pyramidal neurons and their main excitatory afferents, the mossy fiber terminals (MFT), that originate in the dentate gyrus. We report that apical, but not basal, dendritic trees of Golgi-impregnated CA3 principal neurons are significantly shorter, less branched, and less spiny in hypothermic hamsters compared with active animals. After the induction of arousal from torpor, within 2 h, the apical dendritic lengths, branching patterns, and spine density estimations returned to levels found in active, euthermic hamsters. The ultrastructure of MFT in hibernating hamsters showed a significant reduction in synaptic vesicle density and in the percentage of MFT area covered by spine profiles. Awakened hamsters showed restoration of MFT morphology to that seen in active animals. MFT of torpid animals also showed a significant increase in the percentage area of mitochondrial profiles that remained higher 3 h after induced arousal from hibernation compared with euthermic controls. Thus, the torpid/awakening cycle of the hibernating European hamster causes a rapid and reversible morphological reorganization of intrahippocampal subregions involved in information processing. The reported reductions in morphological connectivity between the dentate gyrus and the CA3 subregions could underlie the cessation of exploratory activity and spatial navigation skills during hibernation.
Collapse
Affiliation(s)
- Ana María Magariños
- *The Rockefeller University, 1230 York Avenue, New York, NY 10021; and
- To whom correspondence may be addressed. E-mail:
or
| | - Bruce S. McEwen
- *The Rockefeller University, 1230 York Avenue, New York, NY 10021; and
- To whom correspondence may be addressed. E-mail:
or
| | - Michel Saboureau
- Institut des Neurosciences Cellulaires et Intégratives LC2 7168, Centre National de la Recherche Scientifique-Universite Louis Pasteur, F-67085 Strasbourg, France
| | - Paul Pevet
- Institut des Neurosciences Cellulaires et Intégratives LC2 7168, Centre National de la Recherche Scientifique-Universite Louis Pasteur, F-67085 Strasbourg, France
| |
Collapse
|
17
|
Weltzin MM, Zhao HW, Drew KL, Bucci DJ. Arousal from hibernation alters contextual learning and memory. Behav Brain Res 2005; 167:128-33. [PMID: 16219369 DOI: 10.1016/j.bbr.2005.08.021] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Revised: 08/25/2005] [Accepted: 08/26/2005] [Indexed: 01/12/2023]
Abstract
Hibernation is a unique and highly regulated physiological state characterized by profound, albeit periodically reversible, depression in body temperature, metabolism, and consciousness. Hippocampal synapses undergo pronounced remodeling in concert with torpor and arousal. During hibernation, the number of postsynaptic densities, apical dendritic branches, and spine densities decreases substantially in the hippocampus. Upon arousal these parameters increase beyond pre-hibernation levels and peak within 2-3h. By 24h after arousal, dendritic parameters remain elevated but have started to subside, consistent with pruning and differentiation. The present study examined the functional consequences of these natural changes in synaptic structure. Wild-caught Arctic ground squirrels (AGS) were trained in a hippocampal-dependent contextual fear conditioning task at 3h, 24h, or 4 weeks after arousal (warm-adapted euthermic control group). All groups acquired the fear conditioned response similarly on the training day. During a subsequent retention test session, AGS in the 24h group exhibited enhanced expression of contextual fear compared to the other two groups. These data suggest that the morphological and biochemical changes occurring at 24h after arousal from hibernation affect hippocampal-dependent learning and memory. The natural change in synaptic structure during hibernation may provide a unique opportunity to assess the neural substrates underlying cognitive enhancement.
Collapse
Affiliation(s)
- Maegan M Weltzin
- Alaskan Basic Neuroscience Program, Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775-7000, USA
| | | | | | | |
Collapse
|
18
|
Popova IY, Kokoz YM, Zenchenko KI, Vinogradova OS. The paradoxically high reactivity of septal neurons in hibernating ground squirrels to endogenous neuropeptides is lost after chronic deafferentation of the septum from the preopticohypothalamic areas. Comp Biochem Physiol A Mol Integr Physiol 2003; 135:383-402. [PMID: 12829047 DOI: 10.1016/s1095-6433(03)00088-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effect of neuropeptides (TSKYR, TSKY and DY) and neurotransmitters (serotonin and noradrenaline) on the activity of medial septum (MS) neurons from the brain of summer wakening ground squirrels (WGS), hibernating ground squirrels (HGS), and hibernating ground squirrels with the undercut septum (UHGS) was studied. It was shown that in HGS, the neuropeptides were substantially more effective in modulating the spontaneous activity of MS neurons than in WGS. The undercutting of MS led to the disappearance of the increased responsiveness to the neuropeptides: in UHGS, neuropeptide-induced changes in the spontaneous activity became nearly identical to those in WGS. The decrease in MS responsiveness in UHGS is due mainly to pacemaker neurons, which cease to respond to the peptides. It was shown that the neuropeptides have a dual effect: they change the level of spontaneous activity through direct modulation of pacemaker potential and control responses to electrical stimulation by modulating the synaptic transmission. Contrary to neuropeptides, neurotransmitters were highly effective in neurons of all groups of animals. Presumably, the enhanced excitability of MS during hibernation, which is necessary for performing the 'sentry post' function, is formed under the influence of the preopticohypothalamic area, and this influence is mediated by peptides.
Collapse
Affiliation(s)
- I Yu Popova
- Institute of Theoretical and Experimental Biophysics, Moscow region 142290, Pushchino, Russia.
| | | | | | | |
Collapse
|
19
|
Arousal from hibernation and BAT thermogenesis against cold: central mechanism and molecular basis. J Therm Biol 2002. [DOI: 10.1016/s0306-4565(02)00024-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
20
|
Drew KL, Rice ME, Kuhn TB, Smith MA. Neuroprotective adaptations in hibernation: therapeutic implications for ischemia-reperfusion, traumatic brain injury and neurodegenerative diseases. Free Radic Biol Med 2001; 31:563-73. [PMID: 11522441 DOI: 10.1016/s0891-5849(01)00628-1] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Brains of hibernating mammals are protected against a variety of insults that are detrimental to humans and other nonhibernating species. Such protection is associated with a number of physiological adaptations including hypothermia, increased antioxidant defense, metabolic arrest, leukocytopenia, immunosuppression, and hypocoagulation. It is intriguing that similar manipulations provide considerable protection as experimental treatments for central nervous system injury. This review focuses on neuroprotective mechanisms employed during hibernation that may offer novel approaches in the treatment of stroke, traumatic brain injury, and neurodegenerative diseases in humans.
Collapse
Affiliation(s)
- K L Drew
- Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000, USA.
| | | | | | | |
Collapse
|
21
|
Zenchenko KI, Kokoz YM, Ivanov VT, Ziganshin RH, Vinogradova OS. State-dependent effects of some neuropeptides and neurotransmitters on neuronal activity of the medial septal area in brain slices of the ground squirrel, Citellus undulatus. Neuroscience 2000; 96:791-805. [PMID: 10727797 DOI: 10.1016/s0306-4522(99)00591-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Neuronal activity of the medial septal area was recorded extracellularly in brain slices taken from hibernating (winter) and waking (summer) ground squirrels. The effects of neuropeptides identified in the brain tissue of hibernators (Thr-Ser-Lys-Tyr, Thr-Ser-Lys-Tyr-Arg and Asp-Tyr) on the background activity and responses to electrical stimulation of the median forebrain bundle were analysed. For comparison, the effects of bath application of noradrenaline and serotonin were also tested. Spontaneous activity in half of all neurons (47-56%) was changed under the influence of neuropeptides in hibernating ground squirrels, while in waking ground squirrels the proportion of responsive neurons was significantly lower (25-30%). The tendency for higher efficacy in hibernating ground squirrels was observed for serotonin; only noradrenaline was equally effective in both groups of animals. Electrically evoked responses of the medial septal nucleus-nucleus of the diagonal band neurons were also strongly modulated by neuropeptides; their changes could occur in the absence of shifts in the level and pattern of spontaneous activity. All three neuropeptides had differential action on the level of spontaneous activity, as well as on inhibitory and excitatory components of electrically evoked responses. Thus, the character and distribution of the effects were state dependent and differed greatly in hibernating and waking ground squirrels. The experiments confirmed that medial septal nucleus-nucleus of the diagonal band neurons have higher excitability and responsiveness to some neuropeptides and neurotransmitters in hibernating ground squirrels.The data obtained suggest an increased latent excitability and responsiveness of septal neurons during hibernation and their possible active participation in urgent arousal under the influence of sensory signals.
Collapse
Affiliation(s)
- K I Zenchenko
- Institute of Theoretical and Experimental Biophysics, Puschino, Russia.
| | | | | | | | | |
Collapse
|
22
|
Pakhotin PI, Pavlik LL, Pakhotina ID, Andreev AA. Long-term morphofunctional survival of guinea pig hippocampal slices after brief treatment with cyclooxygenase inhibitors. NEUROSCIENCE AND BEHAVIORAL PHYSIOLOGY 1999; 29:595-8. [PMID: 10596796 DOI: 10.1007/bf02461152] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- P I Pakhotin
- Ecological Acoustics Group, Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region
| | | | | | | |
Collapse
|
23
|
Hashimoto M, Schmid HA, Ohwatari N, Pleschka K. Spontaneous activity of preoptic neurons in slice preparations of the hypothalamus of European hamsters (Cricetus cricetus) and Wistar rats under different states of hypothermia. Cryobiology 1998; 37:254-62. [PMID: 9787070 DOI: 10.1006/cryo.1998.2122] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hypothermia was induced in European hamsters (hibernators) and Wistar rats (nonhibernators), and changes in the firing rate and spike duration of extracellularly recorded action potentials were investigated in hypothalamic slices in vitro. At slice temperatures close to normal body temperature (37 +/- 3 degreesC), 32 and 57% of spontaneously active neurons in the medial preoptic area were classified as warm-sensitive in rats and hamsters, respectively. With decreasing slice temperature, the number of active neurons decreased progressively without a significant difference between rats and hamsters. At a slice temperature of 10 degreesC, 57% of all hypothalamic neurons in rats and 42% in hamsters were still spontaneously active. The average temperature at which activity ceased completely when the temperature was decreased further (the cut-off temperature) was 7.9 +/- 0.3 degreesC (n = 14) in rats but was significantly lower at 4.9 +/- 0.4 degreesC (n = 8) in hamsters (P < 0.001). Firing rates and temperature coefficients did not differ in their temperature dependence between rats and hamsters. Action potential duration increased with decreasing slice temperature in both species, but the increase in duration was significantly greater in rats.
Collapse
Affiliation(s)
- M Hashimoto
- Max-Planck-Institut für Physiologische und Klinische Forschung, W. G. Kerckhoff-Institut, Parkstrasse 1, Bad Nauheim, D-61231, Germany.
| | | | | | | |
Collapse
|
24
|
Kokoz YM, Zenchenko KI, Alekseev AE, Korystova AF, Lankina DA, Ziganshin RH, Mikhaleva II, Ivanov VT. The effect of some peptides from the hibernating brain on Ca2+ current in cardiac cells and on the activity of septal neurons. FEBS Lett 1997; 411:71-6. [PMID: 9247145 DOI: 10.1016/s0014-5793(97)00607-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effects of the peptides TSKYR and DY isolated from the brain of hibernating ground squirrels on Ca2+ current were studied. TSKYR activated Ca2+ current in frog auricle fibers and in single cells from frog ventricle whereas DY blocked Ca2+ current in both preparations. In isolated rat and ground squirrel cardiocytes, TSKYR had no effect on Ca2+ current, and DY increased it. In brain slices of rat, DY blocked the activity of medial septal neurons. TSKYR increased activity of septal neurons at the initial phase, which was followed by decrease of neuronal activity.
Collapse
Affiliation(s)
- Y M Kokoz
- Regulation of Ionic Currents Group, Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Abstract
Varying degrees of metabolic arrest are used by many living species to survive in a harsh environment. For example, in hibernating mammals, neuronal activity and cerebral metabolism are profoundly depressed in most regions of the brain and limited energy resources are deployed to maintain vital cell functions. Gathering evidence suggests that energy resources are also limited in both Alzheimer's and Parkinson's diseases, and that this promotes metabolic stress and the degenerative process. Key steps in this process are energy requiring, and this further compromises cell energy reserves. It may be possible to slow the progress of these diseases by inducing slow-wave sleep (SWS) at night with gammahydroxybutyrate. Patients with these diseases sleep poorly and generate little SWS. SWS and hibernation are thought to be on a continuum of energy conservation. Thus, the induction of SWS may retard the degenerative process by depressing cell metabolism and by directing energy utilization to vital cell functions. In this way, GHB-induced SWS may duplicate the effects of hibernation and extend biologic time.
Collapse
Affiliation(s)
- M Mamelak
- Department of Psychiatry, University of Toronto, Ontario, Canada
| |
Collapse
|
26
|
The influence of hypothermia on the restoration of neural activity of brain slices from hibernating ground squirrels. J Therm Biol 1996. [DOI: 10.1016/s0306-4565(96)00015-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
27
|
Ruby NF, Heller HC. Temperature sensitivity of the suprachiasmatic nucleus of ground squirrels and rats in vitro. J Biol Rhythms 1996; 11:126-36. [PMID: 8744240 DOI: 10.1177/074873049601100205] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Temperature compensation of circadian rhythms in neuronal firing rate was investigated in the suprachiasmatic nucleus (SCN) of ground squirrels and rats in vitro. A reduction in SCN temperature from 37 to 25 degrees C reduced peak firing rates by > 70% in rats but only by approximately 21% in squirrels; trough firing rates were marginally altered in both species. In the rat SCN at 25 degrees C, the peak in neuronal activity decreased progressively on successive days and circadian rhythms no longer were present by Day 3. There was a 37% reduction in the number of single units detected and an increase in the temporal variability of peak firing rates among individual rat SCN neurons at low temperature. By contrast, single units were readily detected and circadian rhythms were robust in squirrels at 37 and 25 degrees C; a Q10 of 0.927 was associated with a shortening of tau by 2 h and a 5-h phase change after only 48 h at low temperature. These results suggest that temperature can have a substantial impact on circadian organization in a mammalian pacemaker considered to be temperature compensated.
Collapse
Affiliation(s)
- N F Ruby
- Department of Biological Sciences, Stanford University, CA 94305-5020, USA
| | | |
Collapse
|
28
|
Nikmanesh FG, Spangenberger H, Igelmund P. Histamine enhances synaptic transmission in hippocampal slices from hibernating and warm-acclimated Turkish hamsters. Neurosci Lett 1996; 210:119-20. [PMID: 8783287 DOI: 10.1016/0304-3940(96)12672-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The effects of histamine on synaptic transmission were studied at 37 degrees C and 22 degrees C with extracellular recordings of stimulus-induced population action potentials in area CA1 of hippocampal slices prepared from hibernating (HTH) and warm-acclimated Turkish hamsters (WTH) and rats. In rat slices, application of 50 microM histamine had no effects on population spikes and field excitatory postsynaptic potentials (EPSPs). In HTH as well as WTH slices, 50 microM histamine generally increased the population spike amplitude. The slope of the field EPSP was unchanged. At 37 degrees C, the sensitivity for histamine was significantly higher in HTH slices than in WTH slices. At 22 degrees C, the effects of histamine were less pronounced in HTH as well as WTH slices. Hibernation-related improvement of sensitivity for histamine is interpreted as supporting hippocampal function during arousal from hibernation.
Collapse
Affiliation(s)
- F G Nikmanesh
- Zentrum Physiologie and Pathophysiologie, Universität zu Köln, Germany
| | | | | |
Collapse
|
29
|
Takahata R, Matsumura H, Eguchi N, Kantha SS, Satoh S, Sakai T, Kondo N, Hayaishi O. Seasonal variation in levels of prostaglandins D2, E2 and F2(alpha) in the brain of a mammalian hibernator, the Asian chipmunk. Prostaglandins Leukot Essent Fatty Acids 1996; 54:77-81. [PMID: 8992498 DOI: 10.1016/s0952-3278(96)90085-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Seasonal changes in the in vivo levels of the prostaglandins (PGs) PGD2, PGE2, and PGF2(alpha) were measured in the brain of the male Asian chipmunk, Tamias asiaticus (n = 111), which underwent hibernation during the period between November and March. The mean level of PGD2 ranged from 36.0 to 85.2 pg/g tissue from June to October and remained essentially unchanged (80.5 pg/g tissue) in December. However, the mean PGD2 level rose significantly to 128.6 pg/g tissue in February, and returned to 75.2 pg/g tissue in the following April, suggesting a correlation between PGD2 and hibernation phenomenon. While PGE2 level did not vary significantly throughout the year, PGF2(alpha), which appeared to be the most abundant among the three prostanoids, showed a marked circannual rhythm with a trough of 51.6 pg/g tissue in July, rising to 391.6 pg/g tissue in February and reaching the peak value of 492.7 pg/g tissue in April, the reproduction period.
Collapse
|
30
|
Nürnberger F. The neuroendocrine system in hibernating mammals: present knowledge and open questions. Cell Tissue Res 1995; 281:391-412. [PMID: 7553762 DOI: 10.1007/bf00417858] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The present review describes the distribution and the function-dependent reactivity pattern of those peptidergic and aminergic components of the neuroendocrine system of hibernating mammals that have been studied by histological, pharmacological and physiological techniques. Particular attention has been paid to the intrinsic connectivity of the peptidergic apparatus and its input systems. Since the reactivity patterns of the neuroendocrine system show remarkable fluctuations in relation to the various stages of hibernation and euthermia, these fluctuations have been analyzed with respect to (1) their causative role in the regulation of hibernation and (2) their secondary response to physiological changes during hibernation. The author's investigations described in this review have mainly been performed in European hedgehogs (Erinaceus europaeus), European and golden hamsters (Cricetus cricetus, Mesocricetus auratus), dormice (Glis glis), and in Richardson's and Columbian ground squirrels (Spermophilus richardsonii, Spermophilus columbianus), by the use of light- and electron-microscopic immunocytochemistry and histochemistry, in situ hybridization, radioimmunoassays and stereotaxically guided application techniques. These experiments were also performed in hypothermic animals. The (partially published) results obtained by the author and his associates are reviewed with reference to the body of evidence found in the recent literature. With respect to their reactivity patterns, several neuropeptide and transmitter systems can be regarded as candidates for control systems of hibernation. Neuronal complexes immunoreactive for endogenous opiates, in particular enkephalin, and also for vasopressin, somatostatin, substance P, corticotropin-releasing factor and serotonin are probably involved in the neuroendocrine control of hibernation.
Collapse
Affiliation(s)
- F Nürnberger
- Zentrum der Morphologie, Klinikum der Johann Wolfgang Goethe-Universität, Frankfurt, Germany
| |
Collapse
|
31
|
Igelmund P, Heinemann U. Synaptic transmission and paired-pulse behaviour of CA1 pyramidal cells in hippocampal slices from a hibernator at low temperature: importance of ionic environment. Brain Res 1995; 689:9-20. [PMID: 8528710 DOI: 10.1016/0006-8993(95)00524-t] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
To investigate the effects of ionic changes possibly associated with hibernation, hippocampal slices prepared from golden hamsters were studied in artificial cerebrospinal fluid (ACSF) of variable composition (K+ 3-5 mM, Ca2+ 2-4 mM, Mg2+ 2-4 mM, pH 7.0-7.7) at temperatures of 15-20 degrees C, just above the temperature below which synaptic transmission is blocked. Population action potentials (population spikes, PSs) of CA1 pyramidal cells were evoked by stimulation of the Schaffer collaterals/commissural fibers with paired pulses (interpulse interval 50 ms, interval between pairs 30 s). The responses evoked at given temperatures were investigated as a function of extracellular ion concentrations. In ACSF containing 3 mM K+, 2 mM Ca2+ and 2 mM Mg2+, PSs could be evoked at temperatures of > approximately 16 degrees C whereas at lower temperatures synaptic transmission was blocked. The threshold temperature was slightly higher for the first (PS1) than for the second PS (PS2) evoked by paired-pulse stimulation. The slices displayed paired-pulse facilitation (PPF) at all temperatures. Elevation of [K+]o from 3 to 5 mM depressed the amplitudes of both PS1 and PS2, with a stronger effect on PS2. PPF was reduced and, at near-threshold temperatures, turned into paired-pulse depression (PPD). Elevation of [Ca2+]o from 2 to 4 mM increased the amplitude of PS1. The amplitude of PS2, in contrast, was reduced at near-threshold temperatures. PPF turned into PPD. Elevation of [Mg2+]o from 2 to 4 mM reduced the amplitudes of both PS1 and PS2, with a stronger effect on PS1. Accordingly, PPF was increased. Acidification by 0.3 pH units strongly depressed the amplitudes of PS1 as well as PS2 and increased PPF. Alkalization by 0.4 pH units had only weak effects in the opposite direction. Changes in the ionic composition comparable to those investigated in the present study presumably occur in the brain interstitium of hamsters during entrance into hibernation. According to our results, such changes depress synaptic transmission at low temperatures in the hamster hippocampus in vitro. This modulation may be important for the regulation of neuronal activity during entrance into hibernation.
Collapse
Affiliation(s)
- P Igelmund
- Zentrum Physiologie und Pathophysiologie, Universität zu Köln, Germany
| | | |
Collapse
|
32
|
Spangenberger H, Nikmanesh FG, Igelmund P. Long-term potentiation at low temperature is stronger in hippocampal slices from hibernating Turkish hamsters compared to warm-acclimated hamsters and rats. Neurosci Lett 1995; 194:127-9. [PMID: 7478194 DOI: 10.1016/0304-3940(95)11723-a] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Tetanus-induced long-term potentiation (LTP) of population action potentials at 22 degrees C was investigated in area CA1 of hippocampal slices prepared from hibernating (HH) and warm-acclimated Turkish hamsters (WH) and rats. LTP elicited at this temperature was significantly stronger in HH slices compared to WH and rat slices. Hibernation-related improvement of the ability to develop long-lasting enhancement of synaptic transmission at low temperatures is interpreted as supporting hippocampal function during arousal from hibernation.
Collapse
Affiliation(s)
- H Spangenberger
- Zentrum Physiologie und Pathophysiologie der Universität zu Köln, Germany
| | | | | |
Collapse
|
33
|
Spangenberger H, Nikmanesh FG, Igelmund P. Effects of adenosine on synaptic transmission in hippocampal slices from hibernating and warm-acclimated Turkish hamsters and rats. Neurosci Lett 1995; 185:217-9. [PMID: 7753495 DOI: 10.1016/0304-3940(95)11262-u] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The effects of adenosine on synaptic transmission were studied with extracellular recordings of stimulus-induced population action potentials in area CA1 of hippocampal slices prepared from hibernating (HH) and warm-acclimated Turkish hamsters (WH) and rats. In HH as well as WH and rat slices, adenosine generally reduced the population spike amplitude and the slope of the field EPSP. The sensitivity for adenosine was significantly lower in HH slices than in WH and rat slices. The results are discussed with regard to the involvement of endogenous adenosine in the regulation of neuronal activity during entrance into and arousal from hibernation.
Collapse
Affiliation(s)
- H Spangenberger
- Zentrum Physiologie und Pathophysiologie, Universität zu Köln, Germany
| | | | | |
Collapse
|
34
|
Abstract
This paper describes preparation of the isolated brain of hibernating ground squirrel maintained by intraarterial perfusion. This technique allows a long-term survival (about 3 days) of the isolated brain of adult animals. The preparation viability was assessed by extracellular investigation of stability of structure-specific electrical activity. The areas investigated include neocortex, hippocampus, thalamus, hypothalamus, and brain stem.
Collapse
Affiliation(s)
- P I Pakhotin
- Institute of Cell Biophysics, Academy of Sciences of Russia, Moscow District
| | | |
Collapse
|