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Todini L, Fantuz F. Thirst: neuroendocrine regulation in mammals. Vet Res Commun 2023; 47:1085-1101. [PMID: 36932281 DOI: 10.1007/s11259-023-10104-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 03/13/2023] [Indexed: 03/19/2023]
Abstract
Animals can sense their changing internal needs and then generate specific physiological and behavioural responses in order to restore homeostasis. Water-saline homeostasis derives from balances of water and sodium intake and output (drinking and diuresis, salt appetite and natriuresis), maintaining an appropriate composition and volume of extracellular fluid. Thirst is the sensation which drives to seek and consume water, regulated in the central nervous system by both neural and chemical signals. Water and electrolyte homeostasis depends on finely tuned physiological mechanisms, mainly susceptible to plasma Na+ concentration and osmotic pressure, but also to blood volume and arterial pressure. Increases of osmotic pressure as slight as 1-2% are enough to induce thirst ("homeostatic" or cellular), by activation of specialized osmoreceptors in the circumventricular organs, outside the blood-brain barrier. Presystemic anticipatory signals (by oropharyngeal or gastrointestinal receptors) inhibit thirst when fluids are ingested, or stimulate thirst associated with food intake. Hypovolemia, arterial hypotension, Angiotensin II stimulate thirst ("hypovolemic thirst", "extracellular dehydration"). Hypervolemia, hypertension, Atrial Natriuretic Peptide inhibit thirst. Circadian rhythms of thirst are also detectable, driven by suprachiasmatic nucleus in the hypothalamus. Such homeostasis and other fundamental physiological functions (cardiocircolatory, thermoregulation, food intake) are highly interdependent.
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Affiliation(s)
- Luca Todini
- Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Via della Circonvallazione 93/95, 62024, Matelica, MC, Italy.
| | - Francesco Fantuz
- Scuola di Bioscienze e Medicina Veterinaria, Università di Camerino, Via della Circonvallazione 93/95, 62024, Matelica, MC, Italy
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2
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Li Z, Shi J, Lei Y, Wu J, Zhang R, Zhang X, Jia L, Wang Y, Ma Y, He P, Ma Y, Cheng Q, Zhang Z, Zhang K, Lei Z. Castration alters the cecal microbiota and inhibits growth in Holstein cattle. J Anim Sci 2022; 100:skac367. [PMID: 36326798 PMCID: PMC9733532 DOI: 10.1093/jas/skac367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 11/03/2022] [Indexed: 11/05/2022] Open
Abstract
To determine the effects of castration on growth performance, serum hormone levels, cecal microbiota composition, and metabolites in cattle. A total of 18 Holstein bulls and steers were divided into bull and steer groups and randomly assigned to 3 pens (3 cattle per pen, and each cattle were separated by a fence) to determine the average daily gain (ADG), daily dry matter intake (DMI), and feed efficiency (G/F). After the finishing trial, six cattle per group were randomly slaughtered. Serum was collected to measure the hormone concentration, and the cecal content was collected to measure the pH, short-chain fatty acids, and digestive enzyme activities. Metagenome sequencing and untargeted metabolomics were used to investigate the microbiota composition, functional profiles, and differential metabolites of the cecal contents. We found that castration significantly decreased ADG, DMI, and G/F in cattle (P < 0.05). The serum testosterone, thyroxine, growth hormone (P < 0.05), and triiodothyronine (P < 0.01) concentrations significantly decreased in the steer group when compared to those of the bull group. The activities of cellulase, xylanase, pectinase, and β-glucosidase (P < 0.05) significantly decreased in the steer group, whereas the activities of lipase and α-amylase significantly increased. Moreover, castration significantly decreased the relative abundance of Ruminococcaceae_bacterium, Treponema_porcinum, Oscillibacter_sp. (P < 0.05), and Alistipes_senegalensis (P < 0.01), whereas the relative abundance of Phocaeicola_plebeius (P < 0.05) was significantly increased. Also, the relative abundance of Phocaeicola_plebeius was negatively correlated with testosterone levels, and the function of the cecal microbiota was enriched in the GH29 and GH97 families in the steer group. Metabolomic analysis indicated that castration increased the levels of L-valine, L-phenylalanine, L-aspartic acid, L-isoleucine, L-lysine, methionine, L-glutamic acid, and L-leucine, while decreasing the levels of α-ketoglutaric acid through the 2-oxocarboxylic acid metabolism pathway. In addition, α-ketoglutaric acid was negatively correlated with Oscillibacter_sp. (P < 0.01). Overall, castration can inhibit cattle growth by altering the composition of the cecal microbiota. Therefore, this study provides a theoretical and practical basis for improving the growth performance of steers.
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Affiliation(s)
- Zemin Li
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Jinping Shi
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Yu Lei
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Jianping Wu
- Institute of Rural Development, Northwest Normal University, Lanzhou, China
| | - Rui Zhang
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Xiao Zhang
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Li Jia
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Ying Wang
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Yue Ma
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Pengjia He
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China
| | - Yannan Ma
- Institute of Rural Development, Northwest Normal University, Lanzhou, China
| | - Qiang Cheng
- Jingchuan Xukang Food Co., Ltd, Pingliang, China
| | - Zhao Zhang
- Gansu Huarui Agriculture Co., Ltd, Zhangye, China
| | - Ke Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Zhaomin Lei
- College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China
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Cai S, Tang AC, Luo TY, Yang SC, Yang H, Liu CX, Shu Y, Pan YC, Zhang Y, Zhou L, Yu T, Yu SY. Effect of basal forebrain somatostatin and parvalbumin neurons in propofol and isoflurane anesthesia. CNS Neurosci Ther 2021; 27:792-804. [PMID: 33764684 PMCID: PMC8193699 DOI: 10.1111/cns.13635] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/03/2021] [Accepted: 03/03/2021] [Indexed: 12/02/2022] Open
Abstract
Aims The basal forebrain (BF) plays an essential role in wakefulness and cognition. Two subtypes of BF gamma‐aminobutyric acid (GABA) neurons, including somatostatin‐expressing (GABASOM) and parvalbumin‐positive (GABAParv) neurons, function differently in mediating the natural sleep–wake cycle. Since the loss of consciousness induced by general anesthesia and the natural sleep–wake cycle probably share similar mechanisms, it is important to clarify the accurate roles of these neurons in general anesthesia procedure. Methods Based on two transgenic mouse lines expressing SOM‐IRES‐Cre and PV‐IRES‐Cre, we used a combination of genetic activation, inactivation, and chronic ablation approaches to further explore the behavioral and electroencephalography (EEG) roles of BFSOM and BFParv neurons in general anesthesia. After a single intravenous injection of propofol and the induction and recovery times of isoflurane anesthesia, the anesthesia time was compared. The changes in cortical EEG under different conditions were also compared. Results Activation of BF GABASOM neurons facilitates both the propofol and isoflurane anesthesia, manifesting as a longer anesthesia duration time with propofol anesthesia and a fast induction time and longer recovery time with isoflurane anesthesia. Moreover, BF GABASOM‐activated mice displayed a greater suppression of cortical electrical activity during anesthesia, showing an increase in δ power bands or a simultaneous decrease in high‐frequency power bands. However, only a limited and nuanced effect on propofol and isoflurane anesthesia was observed with the manipulated BF GABAParv neurons. Conclusions Our results suggested that BF GABASOM neurons play a critical role in propofol and isoflurane general anesthesia, while BF GABAParv neurons appeared to have little effect.
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Affiliation(s)
- Shuang Cai
- Key Laboratory of Brain Science, Zunyi Medical University, Zunyi, China
| | - Ai-Chen Tang
- Key Laboratory of Brain Science, Zunyi Medical University, Zunyi, China
| | - Tian-Yuan Luo
- Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Zunyi, China
| | - Shao-Cheng Yang
- Key Laboratory of Brain Science, Zunyi Medical University, Zunyi, China
| | - Huanhuan Yang
- Key Laboratory of Brain Science, Zunyi Medical University, Zunyi, China
| | - Cheng-Xi Liu
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Zunyi, China
| | - Yue Shu
- Key Laboratory of Brain Science, Zunyi Medical University, Zunyi, China
| | - Yun-Chao Pan
- Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, Zunyi, China
| | - Yu Zhang
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Zunyi, China
| | - Liang Zhou
- Key Laboratory of Brain Science, Zunyi Medical University, Zunyi, China
| | - Tian Yu
- Key Laboratory of Brain Science, Zunyi Medical University, Zunyi, China.,Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, Zunyi, China.,Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Zunyi, China
| | - Shou-Yang Yu
- Key Laboratory of Brain Science, Zunyi Medical University, Zunyi, China
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Stengel A, Taché Y. Central somatostatin signaling and regulation of food intake. Ann N Y Acad Sci 2019; 1455:98-104. [PMID: 31237362 DOI: 10.1111/nyas.14178] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/20/2019] [Accepted: 06/03/2019] [Indexed: 12/29/2022]
Abstract
The discovery of somatostatin (SST) in the hypothalamus implicated the peptide in the inhibition of growth hormone release. However, as observed for numerous neuropeptides, SST was neither restricted to this one brain site nor to this one function. Subsequent studies established a widespread but specific expression of SST in the central nervous system of rodents and humans along with the expression patterns of five receptors (sst1-5 ). Among biological actions, the activation of central SST signaling induced a robust stimulation of food and water intake, which is mediated by the sst2 as assessed using selective sst agonists. The past years have witnessed the identification of brain SST circuitries involved using chemogenetic and optogenetic approaches and further established a physiological orexigenic role of brain SST signaling. The present review will discuss these recent findings.
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Affiliation(s)
- Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany.,Department of Psychosomatic Medicine and Psychotherapy, Medical University Hospital Tübingen, Tübingen, Germany
| | - Yvette Taché
- Department of Medicine, CURE: Digestive Diseases Research Center, Vatche and Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, UCLA, Los Angeles, California.,VA Greater Los Angeles Healthcare System, Los Angeles, California
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5
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Yousefvand S, Hamidi F, Zendehdel M, Parham A. Interaction of neuropeptide Y receptors (NPY1, NPY2 and NPY5) with somatostatin on somatostatin-induced feeding behaviour in neonatal chicken. Br Poult Sci 2018; 60:71-78. [DOI: 10.1080/00071668.2018.1547359] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- S. Yousefvand
- Department of Basic Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - F. Hamidi
- Department of Basic Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
| | - M. Zendehdel
- Department of Basic Sciences, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - A. Parham
- Department of Basic Sciences, Faculty of Veterinary Medicine, Ferdowsi University of Mashhad, Mashhad, Iran
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Genetic Activation, Inactivation, and Deletion Reveal a Limited And Nuanced Role for Somatostatin-Containing Basal Forebrain Neurons in Behavioral State Control. J Neurosci 2018; 38:5168-5181. [PMID: 29735555 DOI: 10.1523/jneurosci.2955-17.2018] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 03/26/2018] [Accepted: 04/24/2018] [Indexed: 11/21/2022] Open
Abstract
Recent studies have identified an especially important role for basal forebrain GABAergic (BFVGAT) neurons in the regulation of behavioral waking and fast cortical rhythms associated with cognition. However, BFVGAT neurons comprise several neurochemically and anatomically distinct subpopulations, including parvalbumin-containing BFVGAT neurons and somatostatin-containing BFVGAT neurons (BFSOM neurons), and it was recently reported that optogenetic activation of BFSOM neurons increases the probability of a wakefulness to non-rapid-eye movement (NREM) sleep transition when stimulated during the rest period of the animal. This finding was unexpected given that most BFSOM neurons are not NREM sleep active and that central administration of the synthetic somatostatin analog, octreotide, suppresses NREM sleep or increases REM sleep. Here we used a combination of genetically driven chemogenetic and optogenetic activation, chemogenetic inhibition, and ablation approaches to further explore the in vivo role of BFSOM neurons in arousal control. Our findings indicate that acute activation or inhibition of BFSOM neurons is neither wakefulness nor NREM sleep promoting and is without significant effect on the EEG, and that chronic loss of these neurons is without effect on total 24 h sleep amounts, although a small but significant increase in waking was observed in the lesioned mice during the early active period. Our in vitro cell recordings further reveal electrophysiological heterogeneity in BFSOM neurons, specifically suggesting at least two distinct subpopulations. Together, our data support the more nuanced view that BFSOM neurons are electrically heterogeneous and are not NREM sleep or wake promoting per se, but may exert, in particular during the early active period, a modest inhibitory influence on arousal circuitry.SIGNIFICANCE STATEMENT The cellular basal forebrain (BF) is a highly complex area of the brain that is implicated in a wide range of higher-level neurobiological processes, including regulating and maintaining normal levels of electrocortical and behavioral arousal. The respective in vivo roles of BF cell populations and their neurotransmitter systems in the regulation of electrocortical and behavioral arousal remains incompletely understood. Here we seek to define the neurobiological contribution of GABAergic somatostatin-containing BF neurons to arousal control. Understanding the respective contribution of BF cell populations to arousal control may provide critical insight into the pathogenesis of a host of neuropsychiatric and neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease, schizophrenia, and the cognitive impairments of normal aging.
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7
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Stengel A, Karasawa H, Taché Y. The role of brain somatostatin receptor 2 in the regulation of feeding and drinking behavior. Horm Behav 2015; 73:15-22. [PMID: 26026616 PMCID: PMC4546908 DOI: 10.1016/j.yhbeh.2015.05.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 05/13/2015] [Accepted: 05/18/2015] [Indexed: 12/13/2022]
Abstract
Somatostatin was discovered four decades ago as hypothalamic factor inhibiting growth hormone release. Subsequently, somatostatin was found to be widely distributed throughout the brain and to exert pleiotropic actions via interaction with five somatostatin receptors (sst1-5) that are also widely expressed throughout the brain. Interestingly, in contrast to the predominantly inhibitory actions of peripheral somatostatin, the activation of brain sst2 signaling by intracerebroventricular injection of stable somatostatin agonists potently stimulates food intake and independently, drinking behavior in rodents. The orexigenic response involves downstream orexin-1, neuropeptide Y1 and μ receptor signaling while the dipsogenic effect is mediated through the activation of the brain angiotensin 1 receptor. Brain sst2 activation is part of mechanisms underlying the stimulation of feeding and more prominently water intake in the dark phase and is able to counteract the anorexic response to visceral stressors.
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Affiliation(s)
- Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Division of General Internal and Psychosomatic Medicine, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, Germany
| | - Hiroshi Karasawa
- CURE: Digestive Diseases Research Center, Center for Neurobiology of Stress and Women's Health, Department of Medicine, Digestive Diseases Division at the University of California Los Angeles, and VA Greater Los Angeles Health Care System, CA 90073, USA
| | - Yvette Taché
- CURE: Digestive Diseases Research Center, Center for Neurobiology of Stress and Women's Health, Department of Medicine, Digestive Diseases Division at the University of California Los Angeles, and VA Greater Los Angeles Health Care System, CA 90073, USA.
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Karasawa H, Yakabi S, Wang L, Stengel A, Rivier J, Taché Y. Brain somatostatin receptor 2 mediates the dipsogenic effect of central somatostatin and cortistatin in rats: role in drinking behavior. Am J Physiol Regul Integr Comp Physiol 2014; 307:R793-801. [PMID: 25031229 DOI: 10.1152/ajpregu.00248.2014] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Intracerebroventricular injection of stable somatostatin (SST) agonists stimulates food and water intake in rats. We investigated the receptor subtype(s) involved in the dipsogenic effect of intracerebroventricular injection of SST agonists, mechanisms of action, and role. In nonfasted and non-water-deprived male rats with chronic intracerebroventricular cannula, intake of water without food or food without water was monitored separately to avoid any interactions compared with intracerebroventricular vehicle. SST-14 and cortistatin (CST-14) (1 μg/rat icv) increased water intake by 3.1- and 2.7-fold, respectively, while both peptides did not alter food intake at 1 h postinjection in the light phase. By contrast, the stable pan-somatostatin agonist ODT8-SST (1 μg/rat icv) increased both water and food intake by 4.9- and 3.7-fold, respectively. S-346-011, a selective receptor 2 (sst2) agonist (1 μg/rat icv) induced water ingestion, while sst1 or sst4 agonist, injected under the same conditions, did not. The sst2 antagonist S-406-028 (1 μg/rat icv) prevented the 1-h water intake induced by intracerebroventricular ODT8-SST and CST-14. Losartan (100 μg/rat icv), an angiotensin receptor 1 (AT1) antagonist, completely blocked the water consumption induced by intracerebroventricular ODT8-SST, whereas intracerebroventricular injection of S-406-028 did not modify the intracerebroventricular ANG II-induced dipsogenic response. The sst2 antagonist reduced by 40% the increase of the 3-h water intake in the early dark phase. These data indicate that SST-14 and CST-14 interact with sst2 to exert a potent dipsogenic effect, which is mediated downstream by angiotensin-AT1 signaling. These data also indicate that sst2 activation by brain SST-14 and/or CST-14 may play an important role in the regulation of drinking behavior.
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Affiliation(s)
- Hiroshi Karasawa
- Department of Medicine, CURE/Digestive Diseases Center, Digestive Diseases Division, University of California at Los Angeles, and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California; and
| | - Seiichi Yakabi
- Department of Medicine, CURE/Digestive Diseases Center, Digestive Diseases Division, University of California at Los Angeles, and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California; and
| | - Lixin Wang
- Department of Medicine, CURE/Digestive Diseases Center, Digestive Diseases Division, University of California at Los Angeles, and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California; and
| | - Andreas Stengel
- Department of Medicine, CURE/Digestive Diseases Center, Digestive Diseases Division, University of California at Los Angeles, and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California; and
| | - Jean Rivier
- The Clayton Foundation Laboratories for Peptide Biology, Salk Institute, La Jolla, California
| | - Yvette Taché
- Department of Medicine, CURE/Digestive Diseases Center, Digestive Diseases Division, University of California at Los Angeles, and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California; and
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Tóth A, Henter T, Détári L. Basal forebrain administration of the somatostatin-analog octreotide does not affect cortical EEG in urethane anaesthetized rats. ACTA PHYSIOLOGICA HUNGARICA 2012; 99:460-71. [PMID: 23238548 DOI: 10.1556/aphysiol.99.2012.4.10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Basal forebrain (BF) plays an important role in the regulation of cortical activation. Somatostatin (SOM) is present both in local neurons as well as in fibers in the BF. In previous studies, SOM axons were found to innervate corticopetal cholinergic cells and SOM was found to presynaptically modulate GABA and glutamate release onto cholinergic neurons in the BF. However, no systematic analysis is available about the EEG effects of SOM or its analog, octreotide (OCTR) injected directly into the BF. In the present experiments, EEG changes were examined following an OCTR injection (0.5 microliter, 500 nmol) into the BF areas containing several choline acetyl transferase-immunoreactive neurons of urethane-anaesthetized rats. Fronto-occipital EEG was recorded on both sides and relative EEG power was calculated in the delta (0-3 Hz), theta (3-9 Hz), alpha (9-16 Hz) and beta (16-48 Hz) frequency bands. OCTR injected to the BF failed to induce significant EEG changes and did not affect tail pinch-evoked cortical activation. Lack of effect may be attributed to the urethane anaesthesia as well as to the possible complex interactions between SOM and BF cholinergic and GABAergic neurons.
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Affiliation(s)
- Attila Tóth
- Department of Physiology and Neurobiology, Eötvös Loránd University, Budapest Hungary
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10
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Engin E, Treit D. Anxiolytic and antidepressant actions of somatostatin: the role of sst2 and sst3 receptors. Psychopharmacology (Berl) 2009; 206:281-9. [PMID: 19609508 DOI: 10.1007/s00213-009-1605-5] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Accepted: 06/26/2009] [Indexed: 12/21/2022]
Abstract
RATIONALE AND OBJECTIVES Somatostatin is a cyclic polypeptide that inhibits the release of a variety of regulatory hormones (e.g., growth hormone, insulin, glucagon, and thyrotropin). Somatostatin is also widely distributed within the central nervous system (CNS), acting both as a neurotransmitter and as a neuromodulator. Recently, we showed that intracerebroventricular (i.c.v.) administration of somatostatin reduced anxiety-like and depression-like behaviors in animal models. The somatostatin receptor subtypes that are involved in these behavioral effects, however, have not been investigated. In the CNS, the neurotransmitter actions of somatostatin are mediated through five G-protein coupled receptors (sst1 to sst5). MATERIALS AND METHODS We examined the behavioral effects of i.c.v. microinfusions of different doses of selective agonists of each of the five somatostatin receptor subtypes. Their behavioral effects were assessed in the elevated plus-maze and the forced swim apparatus, rodent models of anxiolytic and antidepressant drug effects, respectively. RESULTS Anxiety-like behavior was reduced following i.c.v. infusions of a selective sst2 receptor agonist, but not after infusions of the other four receptor agonists. An antidepressant-like effect was observed following infusions of either sst2 or sst3 agonists. CONCLUSIONS The results add to our nascent understanding of the role of somatostatin in anxiety- and depression-like behavior and suggest a clinical role for somatostatin agonists for the simultaneous treatment of anxiety and depression, which are often comorbid.
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Affiliation(s)
- Elif Engin
- Department of Psychology, Centre for Neuroscience, University of Alberta, Edmonton, T6G 2E9, AB, Canada
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Samson WK, Zhang JV, Avsian-Kretchmer O, Cui K, Yosten GLC, Klein C, Lyu RM, Wang YX, Chen XQ, Yang J, Price CJ, Hoyda TD, Ferguson AV, Yuan XB, Chang JK, Hsueh AJW. Neuronostatin encoded by the somatostatin gene regulates neuronal, cardiovascular, and metabolic functions. J Biol Chem 2008; 283:31949-59. [PMID: 18753129 DOI: 10.1074/jbc.m804784200] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Somatostatin is important in the regulation of diverse neuroendocrine functions. Based on bioinformatic analyses of evolutionarily conserved sequences, we predicted another peptide hormone in pro-somatostatin and named it neuronostatin. Immuno-affinity purification allowed the sequencing of an amidated neuronostatin peptide of 13 residues from porcine tissues. In vivo treatment with neuronostatin induced c-Fos expression in gastrointestinal tissues, anterior pituitary, cerebellum, and hippocampus. In vitro treatment with neuronostatin promoted the migration of cerebellar granule cells and elicited direct depolarizing actions on paraventricular neurons in hypothalamic slices. In a gastric tumor cell line, neuronostatin induced c-Fos expression, stimulated SRE reporter activity, and promoted cell proliferation. Furthermore, intracerebroventricular treatment with neuronostatin increased blood pressure but suppressed food intake and water drinking. Our findings demonstrate diverse neuronal, neuroendocrine, and cardiovascular actions of a somatostatin gene-encoded hormone and provide the basis to investigate the physiological roles of this endogenously produced brain/gut peptide.
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Affiliation(s)
- Willis K Samson
- Department of Pharmacological and Physiological Science, Saint Louis University School of Medicine, St. Louis, Missouri 63104, USA.
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12
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Tóth A, Hajnik T, Záborszky L, Détári L. Effect of basal forebrain neuropeptide Y administration on sleep and spontaneous behavior in freely moving rats. Brain Res Bull 2007; 72:293-301. [PMID: 17452289 DOI: 10.1016/j.brainresbull.2007.01.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2006] [Revised: 11/17/2006] [Accepted: 01/09/2007] [Indexed: 10/23/2022]
Abstract
Neuropeptide Y (NPY) is present both in local neurons as well as in fibers in the basal forebrain (BF), an area that plays an important role in the regulation of cortical activation. In our previous experiments in anaesthetized rats, significant EEG changes were found after NPY injections to BF. EEG delta power increased while power in theta, alpha, and beta range decreased. The aim of the present experiments was to determine whether NPY infusion to BF can modulate sleep and behavior in freely moving rats. In this study, microinjections were made into the BF. Saline was injected to the control side, while either saline or one of two doses of NPY (0.5 microl, 300-500 pmol) to the treated side. EEG as well as behavioral changes were recorded. Behavioral elements after the NPY injections changed in a characteristic fashion in time and three consecutive phases were defined. In phase I (half hour 2), activated behavioral items (moving, rearing, grooming) appeared frequently. In phase II (half hours 3 and 4) activity decreased, while motionless state increased. Reappearance of activity was seen in phase III (half hours 5 and 6). NPY injections caused sleep-wake changes. The three phases described for behavioral changes were also reflected in the sleep data. During phase I, lower NPY dose increased wakefulness and decreased deep sleep. Reduced behavioral activity seen in phase II was partially reflected in the sleep. In this phase, wakefulness tended to increase in the third half hour, while decreased in the 4th half hour. Deep sleep and total slow wave sleep non-significantly decreased in the third and increased in the 4th half hour. In most cases, wakefulness was elevated again during Phase III, while sleep decreased. Length of single sleep-wake epochs did not change after NPY injections. Our results suggest a role for NPY in the integration of sleep and behavioral stages via the BF.
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Affiliation(s)
- Attila Tóth
- Department of Physiology and Neurobiology, Eötvös Loránd University, Pázmány Péter Sétány 1/C, H-1117 Budapest, Hungary
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Szentirmai E, Kapás L, Krueger JM. Ghrelin microinjection into forebrain sites induces wakefulness and feeding in rats. Am J Physiol Regul Integr Comp Physiol 2006; 292:R575-85. [PMID: 16917015 DOI: 10.1152/ajpregu.00448.2006] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Ghrelin, a gut-brain peptide, is best known for its role in the stimulation of feeding and growth hormone release. In the brain, orexin, neuropeptide Y (NPY), and ghrelin are parts of a food intake regulatory circuit. Orexin and NPY are also implicated in maintaining wakefulness. Previous experiments in our laboratory revealed that intracerebroventricular injections of ghrelin induce wakefulness in rats. To further elucidate the possible role of ghrelin in the regulation of arousal, we studied the effects of microinjections of ghrelin into hypothalamic sites, which are implicated in the regulation of feeding and sleep, such as the lateral hypothalamus (LH), medial preoptic area (MPA), and paraventricular nucleus (PVN) on sleep in rats. Sleep responses, motor activity, and food intake after central administration of 0.04, 0.2, or 1 mug (12, 60, or 300 pmol) ghrelin were recorded. Microinjections of ghrelin into the LH had strong wakefulness-promoting effects lasting for 2 h. Wakefulness was also stimulated by ghrelin injection into the MPA and PVN; the effects were confined to the first hour after the injection. Ghrelin's non-rapid-eye-movement sleep-suppressive effect was accompanied by attenuation in the electroencephalographic (EEG) slow-wave activity and changes in the EEG power spectrum. Food consumption was significantly stimulated after microinjections of ghrelin into each hypothalamic site. Together, these results are consistent with the hypothesis that forebrain ghrelinergic mechanisms play a role in the regulation of vigilance, possibly through activating the components of the food intake- and arousal-promoting network formed by orexin and NPY.
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Affiliation(s)
- Eva Szentirmai
- Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Neuroscience Program, Washington State University, Pullman, Washington, WA 99164-6520, USA
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Alponti RF, Breno MC, Mancera JM, Martin-Del-Rio MP, Silveira PF. Distribution of somatostatin immunoreactivity in the brain of the snake Bothrops jararaca. Gen Comp Endocrinol 2006; 145:270-9. [PMID: 16288754 DOI: 10.1016/j.ygcen.2005.09.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2005] [Revised: 08/16/2005] [Accepted: 09/16/2005] [Indexed: 10/25/2022]
Abstract
The distribution of perikarya and fibers containing somatostatin was studied in the brain of the snake Bothrops jararaca by means of immunohistochemistry using an antiserum against synthetic somatostatin. Immunoreactive perikarya and fibers were localized in telencephalic, diencephalic and mesencephalic areas. In the telencephalon, numerous immunoreactive perikarya were found in the medial, dorsomedial, dorsal and lateral cortex, mainly in the deep plexiform layer, less so in the cellular layer, but not in the superficial plexiform layer. Immunoreactive perikarya were also observed in the dorsal ventricular ridge, the nucleus of the diagonal band of Broca, amygdaloid complex, septum and lamina terminalis. In the diencephalon, labelled cells were observed in the paraventricular, periventricular hypothalamic and in the recessus infundibular nuclei. In the mesencephalon, immunoreactive perikarya were seen in the mesencephalic reticular formation, reticular nucleus of the isthmus and torus semicircularis. Labelled fibers ran along the diencephalic floor and the inner zone of the median eminence, and ended in the neural lobe of the hypophysis. Other fibers were observed in the outer zone of the median eminence close to the portal vessels and in the septum, lamina terminalis, retrochiasmatic nucleus, deep layers of the tectum, periventricular gray and granular layer of the cerebellum. Our data suggest that somatostatin may function as a mediator of adenohypophysial secretion as well as neurotransmitter and/or neuromodulator which can regulate the neurohypophysial peptides in the snake B. jararaca.
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Affiliation(s)
- R F Alponti
- Laboratory of Pharmacology, Instituto Butantan, Av. Vital Brazil, 1500, 05503-900 São Paulo, SP, Brazil
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Abstract
A significant portion of the total daily growth hormone (GH) secretion is associated with deep non-REM sleep (NREMS). GH secretion is stimulated by the hypothalamic neurohormone, GH-releasing hormone (GHRH). Exogenous GHRH promotes NREMS in various species. Suppression of endogenous GHRH (competitive antagonist, antibodies, somatostatinergic stimulation, high doses of GH or insulin-like growth factor) results in simultaneous inhibition of NREMS. Mutant and transgenic animals with a defect in GHRHergic activity display permanently reduced NREMS which cannot be reversed by means of GH supplementation. GHRH contents and mRNA levels in the hypothalamus correlate with sleep-wake activity during the diurnal cycle and sleep deprivation and recovery sleep. Stimulation of NREMS by GHRH is a hypothalamic action. GABAergic neurons in the anterior hypothalamus/preoptic region are candidates for mediating promotion of NREMS by GHRH. In contrast to NREMS, stimulation of REMS by GHRH is mediated by GH. Simultaneous stimulation of NREMS and GH secretion by GHRH may promote adjustment of tissue anabolism to sleep.
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Affiliation(s)
- Ferenc Obal
- Department of Physiology, A. Szent-Györgyi Medical Center, University of Szeged, 6720, Szeged, Hungary.
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