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Shimoda R, Amaya Y, Okamoto M, Soya S, Soya M, Koizumi H, Nakamura K, Hiraga T, Torma F, Soya H. Accelerated Fear Extinction by Regular Light-Intensity Exercise: A Possible Role of Hippocampal BDNF-TrkB Signaling. Med Sci Sports Exerc 2024; 56:221-229. [PMID: 38214538 DOI: 10.1249/mss.0000000000003312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
PURPOSE Growing concern exists worldwide about stress-related mental disorders, such as posttraumatic stress disorder (PTSD), often linked to hippocampal dysfunctions. Recognizing this connection, regular light-intensity exercise (LIE)-such as yoga, walking, or slow jogging-may offer a solution. Easily accessible even to vulnerable individuals, LIE has been found to enhance hippocampus-based cognitive functions through the stimulation of neurotrophic factors like brain-derived neurotrophic factor (BDNF). A prior study that demonstrated BDNF's role in extinguishing original fear memory further leads us to propose that a consistent LIE training might drive fear extinction learning, offering potential therapeutic benefits through BDNF signaling. METHODS Eleven-week-old Wistar rats underwent 4 wk of training under conditions of sedentary, LIE, or moderate-intensity exercise (MOE) after contextual or auditory fear conditioning. Subsequently, fear extinction tests were performed. We then administered intraperitoneal (i.p.) ANA-12, a selective antagonist of tropomyosin receptor kinase B (TrkB), or a vehicle to explore the role of BDNF signaling in exercise-induced fear extinction among the LIE rats. Following the regular exercise training, further fear extinction tests were conducted, and hippocampal protein analysis was performed using Western blotting. RESULTS Both LIE and MOE over 4 wk accelerated hippocampus-associated contextual fear extinction compared with sedentary. In addition, 4 wk of LIE with i.p. administered vehicle increased hippocampal BDNF and TrkB protein levels. In contrast, i.p. ANA-12 administration fully blocked the LIE-enhanced protein levels and its effect on contextual fear extinction. CONCLUSIONS Our findings reveal that LIE regimen promotes fear extinction learning, at least partially tied to hippocampal BDNF-TrkB signaling. This suggests that even regular light exercise could alleviate the excessive fear response in anxiety disorders and PTSD, providing hope for those affected.
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Affiliation(s)
- Ryo Shimoda
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, JAPAN
| | - Yuki Amaya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, JAPAN
| | | | - Shingo Soya
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Ibaraki, JAPAN
| | - Mariko Soya
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, JAPAN
| | - Hikaru Koizumi
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, JAPAN
| | - Kengo Nakamura
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, JAPAN
| | - Taichi Hiraga
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, JAPAN
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Prolactin-Releasing Peptide Contributes to Stress-Related Mood Disorders and Inhibits Sleep/Mood Regulatory Melanin-Concentrating Hormone Neurons in Rats. J Neurosci 2023; 43:846-862. [PMID: 36564184 PMCID: PMC9899089 DOI: 10.1523/jneurosci.2139-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 08/31/2022] [Accepted: 09/30/2022] [Indexed: 12/24/2022] Open
Abstract
Stress disorders impair sleep and quality of life; however, their pathomechanisms are unknown. Prolactin-releasing peptide (PrRP) is a stress mediator; we therefore hypothesized that PrRP may be involved in the development of stress disorders. PrRP is produced by the medullary A1/A2 noradrenaline (NA) cells, which transmit stress signals to forebrain centers, and by non-NA cells in the hypothalamic dorsomedial nucleus. We found in male rats that both PrRP and PrRP-NA cells innervate melanin-concentrating hormone (MCH) producing neurons in the dorsolateral hypothalamus (DLH). These cells serve as a key hub for regulating sleep and affective states. Ex vivo, PrRP hyperpolarized MCH neurons and further increased the hyperpolarization caused by NA. Following sleep deprivation, intracerebroventricular PrRP injection reduced the number of REM sleep-active MCH cells. PrRP expression in the dorsomedial nucleus was upregulated by sleep deprivation, while downregulated by REM sleep rebound. Both in learned helplessness paradigm and after peripheral inflammation, impaired coping with sustained stress was associated with (1) overactivation of PrRP cells, (2) PrRP protein and receptor depletion in the DLH, and (3) dysregulation of MCH expression. Exposure to stress in the PrRP-insensitive period led to increased passive coping with stress. Normal PrRP signaling, therefore, seems to protect animals against stress-related disorders. PrRP signaling in the DLH is an important component of the PrRP's action, which may be mediated by MCH neurons. Moreover, PrRP receptors were downregulated in the DLH of human suicidal victims. As stress-related mental disorders are the leading cause of suicide, our findings may have particular translational relevance.SIGNIFICANCE STATEMENT Treatment resistance to monoaminergic antidepressants is a major problem. Neuropeptides that modulate the central monoaminergic signaling are promising targets for developing alternative therapeutic strategies. We found that stress-responsive prolactin-releasing peptide (PrRP) cells innervated melanin-concentrating hormone (MCH) neurons that are crucial in the regulation of sleep and mood. PrRP inhibited MCH cell activity and enhanced the inhibitory effect evoked by noradrenaline, a classic monoamine, on MCH neurons. We observed that impaired PrRP signaling led to failure in coping with chronic/repeated stress and was associated with altered MCH expression. We found alterations of the PrRP system also in suicidal human subjects. PrRP dysfunction may underlie stress disorders, and fine-tuning MCH activity by PrRP may be an important part of the mechanism.
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Edwards CM, Guerrero IE, Zheng H, Dolezel T, Rinaman L. Blockade of Ghrelin Receptor Signaling Enhances Conditioned Passive Avoidance and Context-Associated cFos Activation in Fasted Male Rats. Neuroendocrinology 2022; 113:535-548. [PMID: 36566746 PMCID: PMC10133005 DOI: 10.1159/000528828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Interoceptive feedback to the brain regarding the body's physiological state plays an important role in guiding motivated behaviors. For example, a state of negative energy balance tends to increase exploratory/food-seeking behaviors while reducing avoidance behaviors. We recently reported that overnight food deprivation reduces conditioned passive avoidance behavior in male (but not female) rats. Since fasting increases circulating levels of ghrelin, we hypothesized that ghrelin signaling contributes to the ability of fasting to reduce conditioned avoidance. METHODS Ad libitum-fed male rats were trained in a passive avoidance procedure using mild footshock. Later, following overnight food deprivation, the same rats were pretreated with ghrelin receptor antagonist (GRA) or saline vehicle 30 min before avoidance testing. RESULTS GRA restored passive avoidance in fasted rats as measured by both latency to enter and time spent in the shock-paired context. In addition, compared to vehicle-injected fasted rats, fasted rats that received GRA before reexposure to the shock-paired context displayed more cFos activation of prolactin-releasing peptide (PrRP)-positive noradrenergic (NA) neurons in the caudal nucleus of the solitary tract, accompanied by more cFos activation in downstream target sites of PrRP neurons (i.e., bed nucleus of the stria terminalis and paraventricular nucleus of the hypothalamus). DISCUSSION These results support the view that ghrelin signaling contributes to the inhibitory effect of fasting on learned passive avoidance behavior, perhaps by suppressing recruitment of PrRP-positive NA neurons and their downstream hypothalamic and limbic forebrain targets.
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Affiliation(s)
- Caitlyn M Edwards
- Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | | | - Huiyuan Zheng
- Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | - Tyla Dolezel
- Department of Psychology, Florida State University, Tallahassee, Florida, USA
| | - Linda Rinaman
- Department of Psychology, Florida State University, Tallahassee, Florida, USA
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Takahashi K, Shima T, Soya M, Yook JS, Koizumi H, Jesmin S, Saito T, Okamoto M, Soya H. Exercise-Induced Adrenocorticotropic Hormone Response Is Cooperatively Regulated by Hypothalamic Arginine Vasopressin and Corticotrophin-Releasing Hormone. Neuroendocrinology 2022; 112:894-903. [PMID: 34847565 DOI: 10.1159/000521237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 11/30/2021] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Exercise becomes a stress when performed at an intensity above the lactate threshold (LT) because at that point the plasma adrenocorticotropic hormone (ACTH), a marker of stress response, increases. It is possible that the exercise-induced ACTH response is regulated at least by arginine vasopressin (AVP) and possibly by corticotropin-releasing hormone (CRH), but this remains unclear. To clarify the involvement of these factors, it is useful to intervene pharmacologically in the regulatory mechanisms, with a physiologically acceptable exercise model. METHODS We used a special stress model of treadmill running (aerobic exercise) for male Wistar rats, which mimic the human physiological response, where plasma ACTH levels increase at just above the LT for 30 min. Animals were administered the AVP V1b receptor antagonist SSR149415 (SSR) and/or the CRH type 1 receptor antagonist CP154526 (CP) intraperitoneally before the exercise, which allowed the monitoring of exercise-induced ACTH response. Immunohistochemical evaluation of activated AVP and CRH neurons with exercise was performed for the animals' hypothalami. RESULTS A single injection of either antagonist, SSR or CP, resulted in inhibited ACTH levels after exercise stress. Moreover, the combined injection of SSR and CP strongly suppressed ACTH secretion during treadmill running to a greater extent than each alone. The running-exercise-induced activation of both AVP and CRH neurons in the hypothalamus was also confirmed. CONCLUSION These results lead us to hypothesize that AVP and CRH are cooperatively involved in exercise-induced ACTH response just above the LT. This may also reflect the stress response with moderate-intensity exercise in humans.
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Affiliation(s)
- Kanako Takahashi
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
- Division of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Takeru Shima
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
- Department of Health and Physical Education, Cooperative Faculty of Education, Gunma University, Maebashi, Japan
| | - Mariko Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
- Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Jang Soo Yook
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| | - Hikaru Koizumi
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Subrina Jesmin
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Tsuyoshi Saito
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
- Department of Childhood and Education, Shizuoka University of Welfare, Yaizu, Japan
| | - Masahiro Okamoto
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
- Division of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
- Division of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
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Takahashi K, Shima T, Soya M, Oharomari LK, Okamoto M, Soya H. Differences in exercise capacity and physiological responses in Wistar rats among breeders. Exp Anim 2021; 70:508-513. [PMID: 34176861 PMCID: PMC8614012 DOI: 10.1538/expanim.21-0057] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In animal experiments aimed at extrapolation to humans, it is essential to ensure the reproducibility of experiments and universality between animals and humans. However, among animals with
the same generic name but from different breeders, which is to say different stocks, even resting physiological conditions, such as genetics, do not coincide, and, therefore, exercise
capacity and physiological responses may also vary. To address this issue, we examined the differences in exercise capacity and exercise-induced metabolic and endocrine responses among
stocks of Wistar rats using an established treadmill running model for rodents, which mimics physiological responses in humans. Wistar rats from four breeders were acclimated to treadmill
running and then had a catheter inserted into their external jugular veins. Subsequently, the rats were subjected to an incremental treadmill running test (IRT). We found that there were
significant differences in the exercise capacity among Wistar rats from different breeders. Additionally, the dynamics of blood lactate, glucose, and adrenocorticotropic hormone levels
during the IRT were found to vary among the Wistar rats from different breeders; only one stock showed human-type exercise-induced physiological responses. These results indicate that Wistar
rats could have different capacities for and physiological responses to the same exercise depending on their stocks. Thus, the selection of the stock of experimental animals may affect the
validity of the results when verifying exercise effects.
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Affiliation(s)
- Kanako Takahashi
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba.,Division of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba
| | - Takeru Shima
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba.,Department of Health and Physical Education, Cooperative Faculty of Education, Gunma University
| | - Mariko Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba.,Department of Anatomy and Neuroscience, Graduate School of Medical Sciences, Kyushu University
| | - Leandro Kansuke Oharomari
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba
| | - Masahiro Okamoto
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba.,Division of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba.,Division of Sport Neuroscience, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba
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Dysregulation of Glycogen Metabolism with Concomitant Spatial Memory Dysfunction in Type 2 Diabetes: Potential Beneficial Effects of Chronic Exercise. ADVANCES IN NEUROBIOLOGY 2019; 23:363-383. [DOI: 10.1007/978-3-030-27480-1_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Astrocytic glycogen-derived lactate fuels the brain during exhaustive exercise to maintain endurance capacity. Proc Natl Acad Sci U S A 2017; 114:6358-6363. [PMID: 28515312 DOI: 10.1073/pnas.1702739114] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Brain glycogen stored in astrocytes provides lactate as an energy source to neurons through monocarboxylate transporters (MCTs) to maintain neuronal functions such as hippocampus-regulated memory formation. Although prolonged exhaustive exercise decreases brain glycogen, the role of this decrease and lactate transport in the exercising brain remains less clear. Because muscle glycogen fuels exercising muscles, we hypothesized that astrocytic glycogen plays an energetic role in the prolonged-exercising brain to maintain endurance capacity through lactate transport. To test this hypothesis, we used a rat model of exhaustive exercise and capillary electrophoresis-mass spectrometry-based metabolomics to observe comprehensive energetics of the brain (cortex and hippocampus) and muscle (plantaris). At exhaustion, muscle glycogen was depleted but brain glycogen was only decreased. The levels of MCT2, which takes up lactate in neurons, increased in the brain, as did muscle MCTs. Metabolomics revealed that brain, but not muscle, ATP was maintained with lactate and other glycogenolytic/glycolytic sources. Intracerebroventricular injection of the glycogen phosphorylase inhibitor 1,4-dideoxy-1,4-imino-d-arabinitol did not affect peripheral glycemic conditions but suppressed brain lactate production and decreased hippocampal ATP levels at exhaustion. An MCT2 inhibitor, α-cyano-4-hydroxy-cinnamate, triggered a similar response that resulted in lower endurance capacity. These findings provide direct evidence for the energetic role of astrocytic glycogen-derived lactate in the exhaustive-exercising brain, implicating the significance of brain glycogen level in endurance capacity. Glycogen-maintained ATP in the brain is a possible defense mechanism for neurons in the exhausted brain.
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Differential activation of chemically identified neurons in the caudal nucleus of the solitary tract in non-entrained rats after intake of satiating vs. non-satiating meals. Physiol Behav 2014; 136:47-54. [PMID: 24508750 DOI: 10.1016/j.physbeh.2014.01.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/11/2013] [Accepted: 01/20/2014] [Indexed: 12/13/2022]
Abstract
Satiety signals arising from the gastrointestinal (GI) tract and related digestive organs during food ingestion and digestion are conveyed by vagal sensory afferents to the hindbrain nucleus of the solitary tract (NST). Two intermingled but chemically distinct NST neuronal populations have been implicated in meal size control: noradrenergic (NA) neurons that comprise the A2 cell group, and glucagon-like peptide-1 (GLP-1)-positive neurons. Previous results indicate that A2 neurons are activated in a meal size-dependent manner in rats that have been acclimated/entrained to a feeding schedule in order to increase meal size, whereas feeding under the same conditions does not activate GLP-1 neurons. The present study was designed to test the hypothesis that both A2 and GLP-1 neuronal populations are recruited in non-entrained rats after voluntary first-time intake of an unrestricted, satiating volume of liquid Ensure. DBH-positive A2 neurons within the caudal visceral NST were progressively recruited to express cFos in rats that consumed progressively larger volumes of Ensure. Among these DBH-positive neurons, the prolactin-releasing peptide (PrRP)-positive subset was more sensitive to feeding-induced activation than the PrRP-negative subset. Notably, significant activation of GLP-1-positive neurons occurred only in rats that consumed the largest volumes of Ensure, corresponding to nearly 5% of their BW. We interpret these results as evidence that progressive recruitment of NA neurons within the caudal NST, especially the most caudally-situated PrRP-positive subset, effectively "tracks" the magnitude of GI satiety signals and other meal-related sensory feedback. Conversely, GLP-1 neurons may only be recruited in response to the homeostatic challenge of consuming a very large, unanticipated meal.
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Tachibana T, Sakamoto T. Functions of two distinct "prolactin-releasing peptides" evolved from a common ancestral gene. Front Endocrinol (Lausanne) 2014; 5:170. [PMID: 25426099 PMCID: PMC4226156 DOI: 10.3389/fendo.2014.00170] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/29/2014] [Indexed: 12/17/2022] Open
Abstract
Prolactin-releasing peptide (PrRP) is one of the RF-amide peptides and was originally identified in the bovine hypothalamus as a stimulator of prolactin (PRL) release. Independently, another RF-amide peptide was found in Japanese crucian carp and named Carassius-RFa (C-RFa), which shows high homology to PrRP and stimulates PRL secretion in teleost fish. Therefore, C-RFa has been recognized as fish PrRP. However, recent work has revealed that PrRP and C-RFa in non-mammalian vertebrates are encoded by separate genes originated through duplication of an ancestral gene. Indeed, both PrRP and C-RFa are suggested to exist in teleost, amphibian, reptile, and avian species. Therefore, we propose that non-mammalian PrRP (C-RFa) be renamed PrRP2. Despite a common evolutionary origin, PrRP2 appears to be a physiological regulator of PRL, whereas this is not a consistent role for PrRP itself. Further work revealed that the biological functions of PrRP and PrRP2 are not limited solely to PRL release, because they are also neuromodulators of several hypothalamus-pituitary axes and are involved in some brain circuits related to the regulation of food intake, stress, and cardiovascular functions. However, these actions appear to be different among vertebrates. For example, central injection of PrRP inhibits feeding behavior in rodents and teleosts, while it stimulates it in chicks. Therefore, both PrRP and PrRP2 have acquired diverse actions through evolution. In this review, we integrate the burgeoning information of structures, expression profiles, and multiple biological actions of PrRP in higher vertebrates, as well as those of PrRP2 in non-mammals.
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Affiliation(s)
- Tetsuya Tachibana
- Department of Agrobiological Science, Faculty of Agriculture, Ehime University, Matsuyama, Japan
- *Correspondence: Tetsuya Tachibana, Laboratory of Animal Production, Department of Agrobiological Science, Faculty of Agriculture, Ehime University, Matsuyama 790-8566, Japan e-mail:
| | - Tatsuya Sakamoto
- Ushimado Marine Institute, Faculty of Science, Okayama University, Ushimado, Japan
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Lee MC, Okamoto M, Liu YF, Inoue K, Matsui T, Nogami H, Soya H. Voluntary resistance running with short distance enhances spatial memory related to hippocampal BDNF signaling. J Appl Physiol (1985) 2012; 113:1260-6. [DOI: 10.1152/japplphysiol.00869.2012] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Although voluntary running has beneficial effects on hippocampal cognitive functions if done abundantly, it is still uncertain whether resistance running would be the same. For this purpose, voluntary resistance wheel running (RWR) with a load is a suitable model, since it allows increased work levels and resultant muscular adaptation in fast-twitch muscle. Here, we examined whether RWR would have potential effects on hippocampal cognitive functions with enhanced hippocampal brain-derived neurotrophic factor (BDNF), as does wheel running without a load (WR). Ten-week-old male Wistar rats were assigned randomly to sedentary (Sed), WR, and RWR (to a maximum load of 30% of body weight) groups for 4 wk. We found that in RWR, work levels increased with load, but running distance decreased by about half, which elicited muscular adaptation for fast-twitch plantaris muscle without causing any negative stress effects. Both RWR and WR led to improved spatial learning and memory as well as gene expressions of hippocampal BDNF signaling-related molecules. RWR increased hippocampal BDNF, tyrosine-related kinase B (TrkB), and cAMP response element-binding (CREB) protein levels, whereas WR increased only BDNF. With both exercise groups, there were correlations between spatial memory and BDNF protein ( r = 0.41), p-CREB protein ( r = 0.44), and work levels ( r = 0.77). These results suggest that RWR plays a beneficial role in hippocampus-related cognitive functions associated with hippocampal BDNF signaling, even with short distances, and that work levels rather than running distance are more determinant of exercise-induced beneficial effects in wheel running with and without a load.
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Affiliation(s)
- Min Chul Lee
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Institute for Health and Sports Science, University of Tsukuba, Tsukuba, Japan,
- Research Fellow of the Japan Society for the Promotion of Science, Tokyo, Japan; and
| | - Masahiro Okamoto
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Institute for Health and Sports Science, University of Tsukuba, Tsukuba, Japan,
- Research Fellow of the Japan Society for the Promotion of Science, Tokyo, Japan; and
| | - Yu Fan Liu
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Institute for Health and Sports Science, University of Tsukuba, Tsukuba, Japan,
| | - Koshiro Inoue
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Institute for Health and Sports Science, University of Tsukuba, Tsukuba, Japan,
| | - Takashi Matsui
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Institute for Health and Sports Science, University of Tsukuba, Tsukuba, Japan,
| | - Haruo Nogami
- Laboratory of Neuroendocrinology, Institute of Basic Medical Sciences, University of Tsukuba, Tsukuba, Japan
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Institute for Health and Sports Science, University of Tsukuba, Tsukuba, Japan,
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Matsui T, Ishikawa T, Ito H, Okamoto M, Inoue K, Lee MC, Fujikawa T, Ichitani Y, Kawanaka K, Soya H. Brain glycogen supercompensation following exhaustive exercise. J Physiol 2011; 590:607-16. [PMID: 22063629 DOI: 10.1113/jphysiol.2011.217919] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Brain glycogen localized in astrocytes, a critical energy source for neurons, decreases during prolonged exhaustive exercise with hypoglycaemia. However, it is uncertain whether exhaustive exercise induces glycogen supercompensation in the brain as in skeletal muscle. To explore this question, we exercised adult male rats to exhaustion at moderate intensity (20 m min(-1)) by treadmill, and quantified glycogen levels in several brain loci and skeletal muscles using a high-power (10 kW) microwave irradiation method as a gold standard. Skeletal muscle glycogen was depleted by 82-90% with exhaustive exercise, and supercompensated by 43-46% at 24 h after exercise. Brain glycogen levels decreased by 50-64% with exhaustive exercise, and supercompensated by 29-63% (whole brain 46%, cortex 60%, hippocampus 33%, hypothalamus 29%, cerebellum 63% and brainstem 49%) at 6 h after exercise. The brain glycogen supercompensation rates after exercise positively correlated with their decrease rates during exercise. We also observed that cortical and hippocampal glycogen supercompensation were sustained until 24 h after exercise (long-lasting supercompensation), and their basal glycogen levels increased with 4 weeks of exercise training (60 min day(-1) at 20 m min(-1)). These results support the hypothesis that, like the effect in skeletal muscles, glycogen supercompensation also occurs in the brain following exhaustive exercise, and the extent of supercompensation is dependent on that of glycogen decrease during exercise across brain regions. However, supercompensation in the brain preceded that of skeletal muscles. Further, the long-lasting supercompensation of the cortex and hippocampus is probably a prerequisite for their training adaptation (increased basal levels), probably to meet the increased energy demands of the brain in exercising animals.
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Affiliation(s)
- Takashi Matsui
- Laboratory of Exercise Biochemistry & Neuroendocrinology, Institute for Health and Sports Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8574, Ibaraki, Japan
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Matsui T, Soya S, Okamoto M, Ichitani Y, Kawanaka K, Soya H. Brain glycogen decreases during prolonged exercise. J Physiol 2011. [PMID: 21521757 DOI: 10.1113/jphysiol.2011.203570] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Brain glycogen could be a critical energy source for brain activity when the glucose supply from the blood is inadequate (hypoglycaemia). Although untested, it is hypothesized that during prolonged exhaustive exercise that induces hypoglycaemia and muscular glycogen depletion, the resultant hypoglycaemia may cause a decrease in brain glycogen. Here,we tested this hypothesis and also investigated the possible involvement of brain monoamines with the reduced levels of brain glycogen. For this purpose,we exercised male Wistar rats on a treadmill for different durations (30-120 min) at moderate intensity (20 m min⁻¹) and measured their brain glycogen levels using high-power microwave irradiation (10 kW). At the end of 30 and 60 min of running, the brain glycogen levels remained unchanged from resting levels, but liver and muscle glycogen decreased. After 120 min of running, the glycogen levels decreased significantly by ∼37-60% in five discrete brain loci (the cerebellum 60%, cortex 48%, hippocampus 43%, brainstem 37% and hypothalamus 34%) compared to those of the sedentary control. The brain glycogen levels in all five regions after running were positively correlated with the respective blood and brain glucose levels. Further, in the cortex, the levels of methoxyhydroxyphenylglycol (MHPG) and 5-hydroxyindoleacetic acid (5-HIAA), potential involved in degradation of the brain glycogen, increased during prolonged exercise and negatively correlated with the glycogen levels. These results support the hypothesis that brain glycogen could decrease with prolonged exhaustive exercise. Increased monoamines together with hypoglycaemia should be associated with the development of decreased brain glycogen, suggesting a new clue towards the understanding of central fatigue during prolonged exercise.
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Affiliation(s)
- Takashi Matsui
- Laboratory of Exercise Biochemistry and Neuroendocrinology, University of Tsukuba Graduate School of Comprehensive Human Sciences, Tsukuba, Ibaraki, Japan
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Matsui T, Soya S, Okamoto M, Ichitani Y, Kawanaka K, Soya H. Brain glycogen decreases during prolonged exercise. J Physiol 2011; 589:3383-93. [PMID: 21521757 DOI: 10.1113/jphysiol.2010.203570] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Brain glycogen could be a critical energy source for brain activity when the glucose supply from the blood is inadequate (hypoglycaemia). Although untested, it is hypothesized that during prolonged exhaustive exercise that induces hypoglycaemia and muscular glycogen depletion, the resultant hypoglycaemia may cause a decrease in brain glycogen. Here,we tested this hypothesis and also investigated the possible involvement of brain monoamines with the reduced levels of brain glycogen. For this purpose,we exercised male Wistar rats on a treadmill for different durations (30-120 min) at moderate intensity (20 m min⁻¹) and measured their brain glycogen levels using high-power microwave irradiation (10 kW). At the end of 30 and 60 min of running, the brain glycogen levels remained unchanged from resting levels, but liver and muscle glycogen decreased. After 120 min of running, the glycogen levels decreased significantly by ∼37-60% in five discrete brain loci (the cerebellum 60%, cortex 48%, hippocampus 43%, brainstem 37% and hypothalamus 34%) compared to those of the sedentary control. The brain glycogen levels in all five regions after running were positively correlated with the respective blood and brain glucose levels. Further, in the cortex, the levels of methoxyhydroxyphenylglycol (MHPG) and 5-hydroxyindoleacetic acid (5-HIAA), potential involved in degradation of the brain glycogen, increased during prolonged exercise and negatively correlated with the glycogen levels. These results support the hypothesis that brain glycogen could decrease with prolonged exhaustive exercise. Increased monoamines together with hypoglycaemia should be associated with the development of decreased brain glycogen, suggesting a new clue towards the understanding of central fatigue during prolonged exercise.
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Affiliation(s)
- Takashi Matsui
- Laboratory of Exercise Biochemistry and Neuroendocrinology, University of Tsukuba Graduate School of Comprehensive Human Sciences, Tsukuba, Ibaraki, Japan
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Takayanagi Y, Onaka T. Roles of prolactin-releasing peptide and RFamide related peptides in the control of stress and food intake. FEBS J 2010; 277:4998-5005. [DOI: 10.1111/j.1742-4658.2010.07932.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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15
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Onaka T, Takayanagi Y, Leng G. Metabolic and stress-related roles of prolactin-releasing peptide. Trends Endocrinol Metab 2010; 21:287-93. [PMID: 20122847 DOI: 10.1016/j.tem.2010.01.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2009] [Revised: 12/23/2009] [Accepted: 01/07/2010] [Indexed: 12/26/2022]
Abstract
In the modern world, improvements in human health can be offset by unhealthy lifestyle factors, including the deleterious consequences of stress and obesity. For energy homeostasis, humoral factors and neural afferents from the gastrointestinal tract, in combination with long-term nutritional signals, communicate information to the brain to regulate energy intake and expenditure. Energy homeostasis and stress interact with each other, and stress affects both food intake and energy expenditure. Prolactin-releasing peptide, synthesized in discrete neuronal populations in the hypothalamus and brainstem, plays an important role in integrating these responses. This review describes how prolactin-releasing peptide neurons receive information concerning both internal metabolic states and environmental conditions, and play a key role in energy homeostasis and stress responses.
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Affiliation(s)
- Tatsushi Onaka
- Department of Physiology, Jichi Medical University, Shimotsuke-shi, Tochigi-ken 329-0498, Japan
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Ranieri M, Megna M, Lancioni GE, Jirillo E, Amico AP, Nardulli M, Stasi M, Ianieri G, Saggini A, Megna G. Physical exercise and the immune system. Int J Immunopathol Pharmacol 2009; 22:29-32. [PMID: 19887040 DOI: 10.1177/03946320090220s306] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- M Ranieri
- Physical Medicine and Rehabilitation Unit, Neurological and Psychiatric Sciences Department, Aldo Moro University, Bari 70124, Italy.
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Takayanagi Y, Matsumoto H, Nakata M, Mera T, Fukusumi S, Hinuma S, Ueta Y, Yada T, Leng G, Onaka T. Endogenous prolactin-releasing peptide regulates food intake in rodents. J Clin Invest 2008; 118:4014-24. [PMID: 19033670 DOI: 10.1172/jci34682] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Accepted: 09/17/2008] [Indexed: 02/03/2023] Open
Abstract
Food intake is regulated by a network of signals that emanate from the gut and the brainstem. The peripheral satiety signal cholecystokinin is released from the gut following food intake and acts on fibers of the vagus nerve, which project to the brainstem and activate neurons that modulate both gastrointestinal function and appetite. In this study, we found that neurons in the nucleus tractus solitarii of the brainstem that express prolactin-releasing peptide (PrRP) are activated rapidly by food ingestion. To further examine the role of this peptide in the control of food intake and energy metabolism, we generated PrRP-deficient mice and found that they displayed late-onset obesity and adiposity, phenotypes that reflected an increase in meal size, hyperphagia, and attenuated responses to the anorexigenic signals cholecystokinin and leptin. Hypothalamic expression of 6 other appetite-regulating peptides remained unchanged in the PrRP-deficient mice. Blockade of endogenous PrRP signaling in WT rats by central injection of PrRP-specific mAb resulted in an increase in food intake, as reflected by an increase in meal size. These data suggest that PrRP relays satiety signals within the brain and that selective disturbance of this system can result in obesity and associated metabolic disorders.
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Affiliation(s)
- Yuki Takayanagi
- Division of Brain and Neurophysiology, Department of Physiology, Jichi Medical University, Shimotsuke, Tochigi, Japan
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Ogura Y, Naito H, Akin S, Ichinoseki-Sekine N, Kurosaka M, Kakigi R, Sugiura T, Powers SK, Katamoto S, Demirel HA. Elevation of body temperature is an essential factor for exercise-increased extracellular heat shock protein 72 level in rat plasma. Am J Physiol Regul Integr Comp Physiol 2008; 294:R1600-7. [PMID: 18367652 DOI: 10.1152/ajpregu.00581.2007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study examined whether the exercise-increased extracellular heat shock protein 72 (eHsp72) levels in rats was associated with body temperature elevation during exercise. In all, 26 female Sprague-Dawley rats (3 mo old) were assigned randomly to control (CON; n = 8), exercise under warm temperature (WEx; n = 9), or exercise under cold temperature (CEx; n = 9). The WEx and CEx were trained at 25 degrees C or 4 degrees C, respectively, for nine days using a treadmill. Before and immediately after the final exercise bout, the colonic temperatures were measured as an index of body temperature. The animals were subsequently anesthetized, and blood samples were collected and centrifuged. Plasma samples were obtained to assess their eHsp72 levels. Only the colonic temperature in WEx was increased significantly (P < 0.05) by exercise. The eHsp72 level in WEx was significantly higher (P < 0.05) than that of either the CON or CEx. However, no significant difference was found between CON and CEx. Regression analyses revealed that the eHsp72 level increased as a function of the body temperature. In another experiment, the eHsp72 level of animals with body temperature that was passively elevated through similar kinetics to those of the exercise was studied. Results of this experiment showed that mere body temperature elevation was insufficient to induce eHsp72 responses. Collectively, our results suggest that body temperature elevation during exercise is important for induction of exercise-increased eHsp72. In addition, the possible role of body temperature elevation is displayed when the exercise stressor is combined with it.
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Affiliation(s)
- Yuji Ogura
- Institute of Health and Sports Science & Medicine, Juntendo University, Inba, Chiba, Japan
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Tóth ZE, Zelena D, Mergl Z, Kirilly E, Várnai P, Mezey E, Makara GB, Palkovits M. Chronic repeated restraint stress increases prolactin-releasing peptide/tyrosine-hydroxylase ratio with gender-related differences in the rat brain. J Neurochem 2008; 104:653-66. [PMID: 18199117 DOI: 10.1111/j.1471-4159.2007.05069.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In this study, we investigated the effect of chronic repeated restraint (RR) on prolactin-releasing peptide (PrRP) expression. In the brainstem, where PrRP colocalize with norepinephrine in neurons of the A1 and A2 catecholaminergic cell groups, the expression of tyrosine hydroxylase (TH) has also been examined. In the brainstem, but not in the hypothalamus, the basal PrRP expression in female rats was higher than that in the males that was abolished by ovariectomy. RR evoked an elevation of PrRP expression in all areas investigated, with smaller reaction in the brainstems of females. There was no gender-related difference in the RR-evoked TH expression. Elevation of PrRP was relatively higher than elevation of TH, causing a shift in PrRP/TH ratio in the brainstem after RR. Estrogen alpha receptors were found in the PrRP neurons of the A1 and A2 cell groups, but not in the hypothalamus. Bilateral lesions of the hypothalamic paraventricular nucleus did not prevent RR-evoked changes. Elevated PrRP production parallel with increased PrRP/TH ratio in A1/A2 neurons indicate that: (i) there is a clear difference in the regulation of TH and PrRP expression after RR, and (ii) among other factors this may also contribute to the changed sensitivity of the hypothalamo-pituitary-adrenal axis during chronic stress.
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Affiliation(s)
- Zsuzsanna E Tóth
- Neuromorphological and Neuroendocrine Research Laboratory, Department of Anatomy, Histology and Embryology of the Semmelweis University and the Hungarian Academy of Sciences, Budapest, Hungary.
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Abstract
Prolactin-releasing peptide (PrRP) was initially isolated from the bovine hypothalamus as an activating component that stimulated arachidonic acid release from cells stably expressing the orphan G protein-coupled receptor hGR3 (Hinuma et al. 1998) [also known as GPR10 (Marchese et al. 1995), or UHR-1 for the rat orthologue (Welch et al. 1995)]. Initially touted as a prolactin-releasing factor (therefore aptly named prolactin-releasing peptide), the perspective on the function of this peptide in the organism has been greatly expanded. Over 120 papers have been published on this subject since its initial discovery in 1998. Herein I review the state of knowledge of the PrRP system, its putative function in the organism, and implications for therapy.
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Soya H, Mukai A, Deocaris CC, Ohiwa N, Chang H, Nishijima T, Fujikawa T, Togashi K, Saito T. Threshold-like pattern of neuronal activation in the hypothalamus during treadmill running: Establishment of a minimum running stress (MRS) rat model. Neurosci Res 2007; 58:341-8. [PMID: 17524508 DOI: 10.1016/j.neures.2007.04.004] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Revised: 04/04/2007] [Accepted: 04/06/2007] [Indexed: 10/23/2022]
Abstract
Despite the indication that the hypothalamo-pituitary-adrenal (HPA) axis is activated during treadmill running, there have not been any studies focusing on the relationship between exercise intensity and region-specific neural activities in hypothalamus. To address this, rats were subjected to 30 min of running, either at middle (supra-LT, 25 m min(-1)) or low speeds (sub-LT, 15 m min(-1)), and c-Fos-(+) cells were counted and compared with control rats. Significant increases in blood glucose and lactate levels, and plasma ACTH and osmolality levels were observed during supra-LT running. Only supra-LT running significantly increased c-Fos induction in various hypothalamic regions, namely, the medial preoptic area (MPO), periventricular nucleus (Pe), suprachiasmatic nucleus (SCN), supraoptic nucleus (SON), parvocellular division of the paraventricular nucleus (pPVN), anterior hypothalamic area (AH), arcuate nucleus (ARC) and posterior hypothalamic nucleus (PH). However, sub-LT caused no effect on c-Fos accumulation. This indicates that the hypothalamus responds uniquely to running in a threshold-like pattern distinct from the speed-dependent pattern previously reported for the medulla oblongata [Ohiwa et al., 2006a,b]. In addition, these results showed a physiologic basis for mild exercise useful for establishing our minimum running stress (MRS) rat model, or the running conditions that minimize the activation of the HPA axis.
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Affiliation(s)
- Hideaki Soya
- Laboratory of Exercise Biochemistry, University of Tsukuba Graduate School of Comprehensive Human Sciences, Tsukuba 305-8574, Japan.
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