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Rüttgens T, Wolf OT. The influence of a glucose administration on stress responsivity and memory after a socially evaluated cold pressor test. Psychoneuroendocrinology 2022; 142:105803. [PMID: 35605475 DOI: 10.1016/j.psyneuen.2022.105803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 05/12/2022] [Accepted: 05/12/2022] [Indexed: 12/01/2022]
Abstract
The nutritional state of participants prior to stress induction via a laboratory stressor has been demonstrated to influence reactivity of the Hypothalamus-Pituitary-Adrenal axis. So far, either primarily psychosocial or primarily physiological stressors have been utilized investigating this effect. In the present study, we aimed to fill this gap in the existing literature by utilizing a stressor that combines both elements, namely the Socially Evaluated Cold Pressor Test. Furthermore, we investigated how glucose consumption and subsequent stress induction influence long-term memory retrieval as well as working memory. In a 2 × 2 design, half of the 72 participants (36 women, 36 men) participated in the laboratory stressor while the other half participated in a control condition after having fasted for at least six hours. Thirty minutes prior to stress or control treatment, fasted participants consumed either 75 g of glucose or stevia-sweetened water. Salivary cortisol levels, systolic and diastolic blood pressure, as well as affect did not significantly differ between participants consuming glucose or the placebo beverage. Acute stress impaired working memory but had no effect on long-term memory retrieval. Glucose consumption did not significantly influence memory. Our results suggest that the intensity of a stressor might be important when determining the effects of a glucose administration on stress reactivity. The nutritional state of participants taking part in studies investigating the effects of acute stress on memory might be less decisive than previously assumed.
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Affiliation(s)
- Tobias Rüttgens
- Department of Cognitive Psychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Germany
| | - Oliver T Wolf
- Department of Cognitive Psychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr University Bochum, Germany.
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The Case for Clinical Trials with Novel GABAergic Drugs in Diabetes Mellitus and Obesity. Life (Basel) 2022; 12:life12020322. [PMID: 35207609 PMCID: PMC8876029 DOI: 10.3390/life12020322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 02/09/2022] [Accepted: 02/16/2022] [Indexed: 11/17/2022] Open
Abstract
Obesity and diabetes mellitus have become the surprising menaces of relative economic well-being worldwide. Gamma amino butyric acid (GABA) has a prominent role in the control of blood glucose, energy homeostasis as well as food intake at several levels of regulation. The effects of GABA in the body are exerted through ionotropic GABAA and metabotropic GABAB receptors. This treatise will focus on the pharmacologic targeting of GABAA receptors to reap beneficial therapeutic effects in diabetes mellitus and obesity. A new crop of drugs selectively targeting GABAA receptors has been under investigation for efficacy in stroke recovery and cognitive deficits associated with schizophrenia. Although these trials have produced mixed outcomes the compounds are safe to use in humans. Preclinical evidence is summarized here to support the rationale of testing some of these compounds in diabetic patients receiving insulin in order to achieve better control of blood glucose levels and to combat the decline of cognitive performance. Potential therapeutic benefits could be achieved (i) By resetting the hypoglycemic counter-regulatory response; (ii) Through trophic actions on pancreatic islets, (iii) By the mobilization of antioxidant defence mechanisms in the brain. Furthermore, preclinical proof-of-concept work, as well as clinical trials that apply the novel GABAA compounds in eating disorders, e.g., olanzapine-induced weight-gain, also appear warranted.
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Effects of glucose intake on stress reactivity in young, healthy men. Psychoneuroendocrinology 2021; 126:105062. [PMID: 33524887 DOI: 10.1016/j.psyneuen.2020.105062] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 10/23/2020] [Accepted: 11/12/2020] [Indexed: 11/23/2022]
Abstract
The psychobiological stress response has a broad impact on energy metabolism, while the availability of energy may, in turn, affect the stress response. Specifically, a reduced cortisol response has been found after 8-11 hours of fasting, while glucose intake has led to an increase in cortisol reactivity. We compared the effects of standardized glucose or artificial sweetener drinks, as well as water, ingested prior to a physical (cold pressor test, CPT) or a psychosocial stressor (Trier Social Stress Test, TSST) after four hours of fasting. Healthy male subjects (N = 151) were randomized to one of six groups (either glucose, sweetener or water group and stress induction with the CPT or TSST). Thirty minutes after ingestion, participants were exposed to the stressor. Repeated measures of the subjective stress response, salivary cortisol and alpha amylase as well as continuous heart rate recordings were taken to capture the psychobiological stress response. Capillary blood glucose levels were measured four times. We found significant psychobiological stress responses for all variables and both stressors, but significantly stronger responses for the TSST. Moreover, we found a significant but small effect for a slightly stronger cortisol response to stress after glucose ingestion, which is presumably driven by a more pronounced effect in the TSST compared to the CPT condition. Responder rates did not differ for the three conditions in either the TSST or in the CPT. Our results demonstrate that even after a short fasting timeframe of four hours, higher glucose availability results in slightly higher cortisol stress responses in men.
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The 'Jekyll and Hyde' of Gluconeogenesis: Early Life Adversity, Later Life Stress, and Metabolic Disturbances. Int J Mol Sci 2021; 22:ijms22073344. [PMID: 33805856 PMCID: PMC8037741 DOI: 10.3390/ijms22073344] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/18/2021] [Accepted: 03/23/2021] [Indexed: 01/06/2023] Open
Abstract
The physiological response to a psychological stressor broadly impacts energy metabolism. Inversely, changes in energy availability affect the physiological response to the stressor in terms of hypothalamus, pituitary adrenal axis (HPA), and sympathetic nervous system activation. Glucocorticoids, the endpoint of the HPA axis, are critical checkpoints in endocrine control of energy homeostasis and have been linked to metabolic diseases including obesity, insulin resistance, and type 2 diabetes. Glucocorticoids, through the glucocorticoid receptor, activate transcription of genes associated with glucose and lipid regulatory pathways and thereby control both physiological and pathophysiological systemic energy homeostasis. Here, we summarize the current knowledge of glucocorticoid functions in energy metabolism and systemic metabolic dysfunction, particularly focusing on glucose and lipid metabolism. There are elements in the external environment that induce lifelong changes in the HPA axis stress response and glucocorticoid levels, and the most prominent are early life adversity, or exposure to traumatic stress. We hypothesise that when the HPA axis is so disturbed after early life adversity, it will fundamentally alter hepatic gluconeogenesis, inducing hyperglycaemia, and hence crystalise the significant lifelong risk of developing either the metabolic syndrome, or type 2 diabetes. This gives a “Jekyll and Hyde” role to gluconeogenesis, providing the necessary energy in situations of acute stress, but driving towards pathophysiological consequences when the HPA axis has been altered.
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Zhou YT, He ZG, Liu TT, Feng MH, Zhang DY, Xiang HB. Neuroanatomical circuitry between kidney and rostral elements of brain: a virally mediated transsynaptic tracing study in mice. ACTA ACUST UNITED AC 2017; 37:63-69. [PMID: 28224417 DOI: 10.1007/s11596-017-1695-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/14/2016] [Indexed: 12/13/2022]
Abstract
The identity of higher-order neurons and circuits playing an associative role to control renal function is not well understood. We identified specific neural populations of rostral elements of brain regions that project multisynaptically to the kidneys in 3-6 days after injecting a retrograde tracer pseudorabies virus (PRV)-614 into kidney of 13 adult male C57BL/6J strain mice. PRV-614 infected neurons were detected in a number of mesencephalic (e.g. central amygdala nucleus), telencephalic regions and motor cortex. These divisions included the preoptic area (POA), dorsomedial hypothalamus (DMH), lateral hypothalamus, arcuate nucleus (Arc), suprachiasmatic nucleus (SCN), periventricular hypothalamus (PeH), and rostral and caudal subdivision of the paraventricular nucleus of the hypothalamus (PVN). PRV-614/Tyrosine hydroxylase (TH) double-labeled cells were found within DMH, Arc, SCN, PeH, PVN, the anterodorsal and medial POA. A subset of neurons in PVN that participated in regulating sympathetic outflow to kidney was catecholaminergic or serotonergic. PRV-614 infected neurons within the PVN also contained arginine vasopressin or oxytocin. These data demonstrate the rostral elements of brain innervate the kidney by the neuroanatomical circuitry.
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Affiliation(s)
- Ye-Ting Zhou
- Department of Surgery, Shuyang Hospital, Shuyang, 223600, China
| | - Zhi-Gang He
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Tao-Tao Liu
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Mao-Hui Feng
- Department of Oncology, Wuhan Peritoneal Cancer Clinical Medical Research Center, Zhangnan Hospital of Wuhan University, Wuhan, 430071, China.
| | - Ding-Yu Zhang
- Intensive Care Unit, Wuhan Medical Treatment Center, Wuhan, 430023, China.
| | - Hong-Bing Xiang
- Department of Anesthesiology and Pain Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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Cohen S, Vainer E, Matar MA, Kozlovsky N, Kaplan Z, Zohar J, Mathé AA, Cohen H. Diurnal fluctuations in HPA and neuropeptide Y-ergic systems underlie differences in vulnerability to traumatic stress responses at different zeitgeber times. Neuropsychopharmacology 2015; 40:774-90. [PMID: 25241802 PMCID: PMC4289967 DOI: 10.1038/npp.2014.257] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 09/15/2014] [Indexed: 11/09/2022]
Abstract
The hypothalamic-pituitary-adrenal (HPA) axis displays a characteristic circadian pattern of corticosterone release, with higher levels at the onset of the active phase and lower levels at the onset of the inactive phase. As corticosterone levels modify the response to stress and influence the susceptibility to and/or severity of stress-related sequelae, we examined the effects of an acute psychological trauma applied at different zeitgeber times (ZTs) on behavioral stress responses. Rats were exposed to stress either at the onset of the inactive-(light) phase (ZT=0) or at the onset of the active-(dark) phase (ZT=12). Their behavior in the elevated plus-maze and acoustic startle response paradigms were assessed 7 days post exposure for retrospective classification into behavioral response groups. Serum corticosterone levels and the dexamethasone suppression test were used to assess the stress response and feedback inhibition of the HPA axis. Immunoreactivity for neuropeptide Y (NPY) and NPY-Y1 receptor (Y1R) in the paraventricular (PVN) and arcuate (ARC) hypothalamic nuclei, hippocampus, and basolateral amygdala were measured. The behavioral effects of NPY/Y1R antagonist microinfused into the PVN 30 min before stress exposure during the inactive or active phase, respectively, were evaluated. PVN immunoreactivity for NPY and Y1R was measured 1 day after the behavioral tests. The time of day of the traumatic exposure markedly affected the pattern of the behavioral stress response and the prevalence of rats showing an extreme behavioral response. Rats exposed to the stressor at the onset of their inactive phase displayed a more traumatic behavioral response, faster post-exposure corticosterone decay, and a more pronounced stress-induced decline in NPY and Y1R expression in the PVN and arcuate hypothalamic nuclei. Blocking PVN Y1R before stress applied in the active phase, or administering NPY to the PVN before stress applied in the inactive phase, had a resounding behavioral effect. The time at which stress occurred significantly affected the behavioral stress response. Diurnal variations in HPA and NPY/Y1R significantly affect the behavioral response, conferring more resilience at the onset of the active phase and more vulnerability at the onset of the inactive phase, implying that NPY has a significant role in conferring resilience to stress-related psychopathology.
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Affiliation(s)
- Shlomi Cohen
- Faculty of Health Sciences, Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Ministry of Health, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Department of Psychology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ella Vainer
- Faculty of Health Sciences, Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Ministry of Health, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Michael A Matar
- Faculty of Health Sciences, Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Ministry of Health, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Nitsan Kozlovsky
- Faculty of Health Sciences, Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Ministry of Health, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Zeev Kaplan
- Faculty of Health Sciences, Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Ministry of Health, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Joseph Zohar
- Division of Psychiatry, State of Israel Ministry of Health, Chaim Sheba Medical Center, Sackler Medical School, Tel-Aviv University, Ramat-Gan, Israel
| | - Aleksander A Mathé
- Department of Neuroscience, Karolinska Institutet—Clinical Neuroscience, Karolinska University Hospital Huddinge, Stockholm, Sweden
| | - Hagit Cohen
- Faculty of Health Sciences, Anxiety and Stress Research Unit, Beer-Sheva Mental Health Center, Ministry of Health, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- Department of Psychology, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Chong AC, Vogt MC, Hill AS, Brüning JC, Zeltser LM. Central insulin signaling modulates hypothalamus-pituitary-adrenal axis responsiveness. Mol Metab 2014; 4:83-92. [PMID: 25685696 PMCID: PMC4314547 DOI: 10.1016/j.molmet.2014.12.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 11/26/2014] [Accepted: 12/01/2014] [Indexed: 12/29/2022] Open
Abstract
Objective Obesity is often accompanied by hyperactivity of the neuroendocrine stress axis and has been linked to an increased risk of psychiatric disorders. Insulin is reciprocally regulated with the stress hormone corticosterone (CORT), raising the possibility that insulin normally provides inhibitory tone to the hypothalamus-adrenal-pituitary (HPA) axis. Here we examined whether disrupting signaling via the insulin receptor (InsR) in hypothalamic subpopulations impacts the neuroendocrine response to acute psychological stress. Methods We used Nkx2.1-Cre, Sim1-Cre and Agrp-Cre transgenic driver lines to generate conditional knockouts of InsR signaling throughout the hypothalamus, paraventricular nucleus of the hypothalamus (PVH) and in neurons expressing Agouti-related peptide (AgRP) in the arcuate nucleus of the hypothalamus (ARH), respectively. We used a combination of molecular, behavioral and neuroendocrine criteria to evaluate the consequences on HPA axis responsiveness. Results Endpoints related to body weight and glucose homeostasis were not altered in any of the conditional mutant lines. Consistent with observations in the neuronal Insr knockout mice (NIRKO), baseline levels of serum CORT were similar to controls in all three lines. In male mice with broad disruptions of InsR signals in Nkx2.1-expressing regions of the hypothalamus (IRNkx2.1 KO), we observed elevated arginine vasopressin (AVP) levels at baseline and heightened neuroendocrine responses to restraint stress. IRNkx2.1 KO males also exhibited increased anxiety-like behaviors in open field, marble burying, and stress-induced hyperthermia testing paradigms. HPA axis responsivity was not altered in IRSim1 KO males, in which InsR was disrupted in the PVH. In contrast to observations in the IRNkx2.1 KO males, disrupting InsR signals in ARH neurons expressing Agrp (IRAgrp KO) led to reduced AVP release in the median eminence (ME). Conclusions We find that central InsR signals modulate HPA responsivity to restraint stress. InsR signaling in AgRP/NPY neurons appears to promote AVP release, while signaling in other hypothalamic neuron(s) likely acts in an opposing fashion. Alterations in InsR signals in neurons that integrate metabolic and psychiatric information could contribute to the high co-morbidity of obesity and mental disorders.
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Key Words
- ACTH, adrenocorticotropic hormone
- ARH, arcuate nucleus of the hypothalamus
- AVP, arginine vasopressin
- AgRP
- AgRP, agouti-related peptide
- CORT, corticosterone
- CRH, corticotropin-releasing hormone
- FST, forced swim test
- Gr, Glucocorticoid receptor
- HPA axis
- HPA axis, Hypothalamus–Pituitary–Adrenal axis
- Hypothalamus
- IRAgrp KO, knockout of InsR using Agrp-Cre
- IRNkx2.1 KO, knockout of InsR using Nkx2.1-Cre
- IRSim1 KO, knockout of InsR using Sim1-Cre
- InsR, insulin receptor
- Insulin
- MB, marble burying test
- MBH, mediobasal hypothalamus
- ME, median eminence
- NPY, neuropeptide Y
- NSF, novelty suppressed feeding test
- OF, open field test
- POMC, pro-opiomelanocortin
- SIH, stress-induced hyperthermia test
- Stress response
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Affiliation(s)
- Angie C.N. Chong
- Naomi Berrie Diabetes Center, Columbia University, New York, NY 10032, USA
| | - Merly C. Vogt
- Max-Planck-Institute for Metabolism Research, 50931 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50674 Cologne, Germany
| | - Alexis S. Hill
- Division of Integrative Neuroscience, Departments of Neuroscience and Psychiatry, Department of Pharmacology, Columbia University New York, NY 10032, USA
| | - Jens C. Brüning
- Max-Planck-Institute for Metabolism Research, 50931 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50674 Cologne, Germany
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, 50924 Cologne, Germany
| | - Lori M. Zeltser
- Naomi Berrie Diabetes Center, Columbia University, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
- Corresponding author. Naomi Berrie Diabetes Center, Columbia University, 1150 St Nicholas Ave, New York, NY 10032, USA. Tel.: +1 (212) 851 5314; fax: +1 (212) 851 6306.
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Poitras VJ, Slattery DJ, Gurd BJ, Pyke KE. Evidence that meal fat content does not impact hemodynamic reactivity to or recovery from repeated mental stress tasks. Appl Physiol Nutr Metab 2014; 39:1314-21. [PMID: 25238201 DOI: 10.1139/apnm-2014-0111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The magnitude (reactivity) and duration (recovery) of hemodynamic stress responses are predictive of cardiovascular risk, and fat intake has been shown to enhance hemodynamic reactivity to psychological stress tasks. The objective of this study was to determine the impact of a high-fat meal (HFM) on the magnitude and stability of hemodynamic stress reactivity and recovery. This was assessed by: (i) the peak changes from baseline to during stress for heart rate (HR); mean, systolic, and diastolic blood pressure; cardiac output; and total peripheral resistance; and (ii) the residual arousal in hemodynamic parameters at 2 points post-stress ("early" and "late" recovery). On different days, 10 healthy males (aged 23.2 ± 3.3 years) consumed either a HFM (54 g fat) or low-fat meal (LFM; 0 g fat) (∼1000 calories each), followed by 4 hourly 10-min stress tasks (mental arithmetic and speech tasks). Pre-stress (baseline) parameters did not differ between HFM and LFM conditions (all P > 0.05). Plasma triglycerides were greater following the HFM versus the LFM (P = 0.023). No reactivity or recovery parameters differed between meals (all P > 0.05). Stress reactivity and recovery parameters were stable over the 4 stress tasks (main effects of time, all P > 0.05), with the exception of HR (P < 0.05). Contrary to previous reports, meal fat content did not impact hemodynamic reactivity to laboratory stressors. These data also provide the first evidence that meal fat content does not impact hemodynamic recovery from repeated mental stress tasks.
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Affiliation(s)
- Veronica J Poitras
- School of Kinesiology and Health Studies, Queen's University, Kingston, ON K7L 3N6, Canada
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Resch JM, Maunze B, Gerhardt AK, Magnuson SK, Phillips KA, Choi S. Intrahypothalamic pituitary adenylate cyclase-activating polypeptide regulates energy balance via site-specific actions on feeding and metabolism. Am J Physiol Endocrinol Metab 2013; 305:E1452-63. [PMID: 24148346 PMCID: PMC3882380 DOI: 10.1152/ajpendo.00293.2013] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Numerous studies have demonstrated that both the hypothalamic paraventricular nuclei (PVN) and ventromedial nuclei (VMN) regulate energy homeostasis through behavioral and metabolic mechanisms. Receptors for pituitary adenylate cyclase-activating polypeptide (PACAP) are abundantly expressed in these nuclei, suggesting PACAP may be critical for the regulation of feeding behavior and body weight. To characterize the unique behavioral and physiological responses attributed to select hypothalamic cell groups, PACAP was site-specifically injected into the PVN or VMN. Overall food intake was significantly reduced by PACAP at both sites; however, meal pattern analysis revealed that only injections into the PVN produced significant reductions in meal size, duration, and total time spent eating. PACAP-mediated hypophagia in both the PVN and VMN was abolished by PAC1R antagonism, whereas pretreatment with a VPACR antagonist had no effect. PACAP injections into the VMN produced unique changes in metabolic parameters, including significant increases in core body temperature and spontaneous locomotor activity that was PAC1R dependent whereas, PVN injections of PACAP had no effect. Finally, PACAP-containing afferents were identified using the neuronal tracer cholera toxin subunit B (CTB) injected unilaterally into the PVN or VMN. CTB signal from PVN injections was colocalized with PACAP mRNA in the medial anterior bed nucleus of the stria terminalis, VMN, and lateral parabrachial nucleus (LPB), whereas CTB signal from VMN injections was highly colocalized with PACAP mRNA in the medial amygdala and LPB. These brain regions are known to influence energy homeostasis perhaps, in part, through PACAP projections to the PVN and VMN.
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Affiliation(s)
- Jon M Resch
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin
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Resch JM, Boisvert JP, Hourigan AE, Mueller CR, Yi SS, Choi S. Stimulation of the hypothalamic ventromedial nuclei by pituitary adenylate cyclase-activating polypeptide induces hypophagia and thermogenesis. Am J Physiol Regul Integr Comp Physiol 2011; 301:R1625-34. [PMID: 21957159 DOI: 10.1152/ajpregu.00334.2011] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Numerous studies have demonstrated that the hypothalamic ventromedial nuclei (VMN) regulate energy homeostasis by integrating and utilizing behavioral and metabolic mechanisms. The VMN heavily express pituitary adenylate cyclase-activating polypeptide (PACAP) type I receptors (PAC1R). Despite the receptor distribution, most PACAP experiments investigating affects on feeding have focused on intracerebroventricular administration or global knockout mice. To identify the specific contribution of PACAP signaling in the VMN, we injected PACAP directly into the VMN and measured feeding behavior and indices of energy expenditure. Following an acute injection of PACAP, nocturnal food intake was significantly reduced for 6 h after injections without evidence of malaise. In addition, PACAP-induced suppression of feeding also occurred following an overnight fast and could be blocked by a specific PAC1R antagonist. Metabolically, VMN-specific injections of PACAP significantly increased both core body temperature and spontaneous locomotor activity with a concurrent increase in brown adipose uncoupling protein 1 mRNA expression. To determine which signaling pathways were responsive to PACAP administration into the VMN, we measured mRNA expression of well-characterized hypothalamic neuropeptide regulators of feeding. One hour after PACAP administration, expression of pro-opiomelanocortin mRNA was significantly increased in the arcuate nuclei (ARC), with no changes in neuropeptide Y and agouti-related polypeptide mRNA levels. This suggests that PAC1R expressing VMN neurons projecting to pro-opiomelanocortin neurons contribute to hypophagia by involving melanocortin signaling. While the VMN also abundantly express PACAP protein, the present study demonstrates that PACAP input to the VMN can influence the control of energy homeostasis.
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Affiliation(s)
- Jon M Resch
- Department of Biomedical Sciences, Marquette University, Milwaukee, Wisconsin, USA
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Dallman MF, Bhatnagar S. Chronic Stress and Energy Balance: Role of the Hypothalamo‐Pituitary‐Adrenal Axis. Compr Physiol 2011. [DOI: 10.1002/cphy.cp070410] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Hamer M, Owen G, Kloek J. The role of functional foods in the psychobiology of health and disease. Nutr Res Rev 2007; 18:77-88. [DOI: 10.1079/nrr2005103] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
AbstractThe effect of psychological stress on health is becoming a serious concern, with figures from the World Health Organization showing that stress-related disorders affect nearly 450 million individuals worldwide. Heightened physiological stress responses and psychosocial factors have been linked to disease pathways such as hypertension and CVD. This has prompted significant interest within the scientific community, public health bodies and industry to employ interventions to control and reduce the impact of stress on health. There is now strong potential for functional foods to offer stress management benefits. Various physiological pathways have been targeted by specific dietary supplements for stress reduction, including the hypothalamic–pituitary–adrenal axis and sympathetic nervous system. Presently there are a number of ingredients, which include vitamin C, milk proteins, a number of herbal extracts (ginkgo biloba, ginseng, kava, valerian and lemon balm), andn-3 fatty acids, that have demonstrated potential stress reactivity-lowering and mood-enhancing effects, although further work is required to substantiate the efficacy in human subjects. Dietary supplements that can alleviate excessive stress responses may play an increasingly important role for the maintenance of health in a stressful environment. However, future research should employ a greater range of measures that will provide stronger evidence to substantiate functional food claims for stress relief.
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Gorton LM, Khan AM, Bohland M, Sanchez-Watts G, Donovan CM, Watts AG. A role for the forebrain in mediating time-of-day differences in glucocorticoid counterregulatory responses to hypoglycemia in rats. Endocrinology 2007; 148:6026-39. [PMID: 17823259 DOI: 10.1210/en.2007-0194] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The time of day influences the magnitude of ACTH and corticosterone responses to hypoglycemia. However, little is known about the mechanisms that impart these time-of-day differences on neuroendocrine CRH neurons in the hypothalamic paraventricular nucleus (PVH). Rats received 0-3 U/kg insulin (or 0.9% saline) to achieve a range of glucose nadir concentrations. Brains were processed to identify phosphorylated ERK1/2 (phospho-ERK1/2)-immunoreactive cells in the PVH and hindbrain and CRH heteronuclear RNA in the PVH. Hypoglycemia did not stimulate ACTH and corticosterone responses in animals unless a glucose concentration of approximately 3.15 mM or below was reached. Critically the glycemic thresholds required to stimulate ACTH and corticosterone release in the morning and night were indistinguishable. Yet glucose concentrations below the estimated glycemic threshold correlated with a greater increase in corticosterone, ACTH, and phospho-ERK1/2-immunoreactive neurons in the PVH at night, compared with morning. In these same animals, the number of phospho-ERK1/2-immunoreactive neurons in the medial part of the nucleus of the solitary tract was unchanged at both times of day. These data collectively support a model whereby changes in forebrain mechanisms alter the sensitivity of neuroendocrine CRH to the hypoglycemia-related information conveyed by ascending catecholaminergic afferents. Circadian clock-driven processes together with glucose-sensing elements in the forebrain would seem to be strong contenders for mediating these effects.
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Affiliation(s)
- Lori M Gorton
- The Neuroscience Research Institute, Hedco Neuroscience Building, University of Southern California, Los Angeles, CA 90089-2520, USA
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DAS MAHASWETA, VIHLEN CHRISTOPHERS, LEGRADI GABOR. Hypothalamic and brainstem sources of pituitary adenylate cyclase-activating polypeptide nerve fibers innervating the hypothalamic paraventricular nucleus in the rat. J Comp Neurol 2007; 500:761-76. [PMID: 17154257 PMCID: PMC1934940 DOI: 10.1002/cne.21212] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The hypothalamic paraventricular nucleus (PVN) coordinates major neuroendocrine and behavioral mechanisms, particularly responses to homeostatic challenges. Parvocellular and magnocellular PVN neurons are richly innervated by pituitary adenylate cyclase-activating polypeptide (PACAP) axons. Our recent functional observations have also suggested that PACAP may be an excitatory neuropeptide at the level of the PVN. Nevertheless, the exact localization of PACAP-producing neurons that project to the PVN is not understood. The present study examined the specific contribution of various brain areas sending PACAP innervation to the rat PVN by using iontophoretic microinjections of the retrograde neuroanatomical tracer cholera toxin B subunit (CTb). Retrograde transport was evaluated from hypothalamic and brainstem sections by using multiple labeling immunofluorescence for CTb and PACAP. PACAP-containing cell groups were found to be retrogradely labeled from the PVN in the median preoptic nucleus; preoptic and lateral hypothalamic areas; arcuate, dorsomedial, ventromedial, and supramammillary nuclei; ventrolateral midbrain periaqueductal gray; rostral and midlevel ventrolateral medulla, including the C1 catecholamine cell group; nucleus of the solitary tract; and dorsal motor nucleus of vagus. Minor PACAP projections with scattered double-labeled neurons originated from the parabrachial nucleus, pericoeruleus area, and caudal regions of the nucleus of the solitary tract and ventrolateral medulla. These observations indicate a multisite origin of PACAP innervation to the PVN and provide a strong chemical neuroanatomical foundation for interaction between PACAP and its potential target neurons in the PVN, such as parvocellular CRH neurons, controlling physiologic responses to stressful challenges and other neuroendocrine or preautonomic PVN neurons.
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Affiliation(s)
| | | | - GABOR LEGRADI
- *Correspondence to: Gabor Legradi, MD, Department of Pathology and Cell Biology, College of Medicine University of South Florida, 12901 Bruce B. Downs Blvd., MDC6, Tampa, FL 33612-4799. E-mail:
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15
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Tran PV, Akana SF, Malkovska I, Dallman MF, Parada LF, Ingraham HA. Diminished hypothalamic bdnf expression and impaired VMH function are associated with reduced SF-1 gene dosage. J Comp Neurol 2006; 498:637-48. [PMID: 16917842 DOI: 10.1002/cne.21070] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In the central nervous system, steroidogenic factor 1 (SF-1) is required for terminal differentiation of neurons within the ventromedial hypothalamus (VMH). Given the importance of this brain region in regulating physiological homeostasis including energy balance, we asked how sf-1 gene dosage affects VMH function. Despite an apparent normal VMH cytoarchitecture, sf-1 heterozygous (+/-) mice exhibited diet-induced obesity when they were group housed with hyperphagia and impaired sympathetic activity. On the basis of previous findings suggesting brain-derived neurotrophic factor (bdnf) as an SF-1 target gene, we assessed the colocalization of SF-1 and BDNF expressing neurons, as well as expression of the four exon-specific bdnf promoter transcripts in the VMH. Indeed, a subset of neurons located primarily in the ventrolateral VMH coexpress SF-1 and BDNF, and in contrast to other brain regions, bdnf I, II, and IV but not III are found. Consistent with these findings, cellular assays showed that SF-1 is able to activate exon I and IV promoters. More important, levels of bdnf I and IV in the VMH were reduced in heterozygous mice similar to levels observed in fasted wild-type mice. Collectively, we propose that a reduction in the sf-1 gene dosage directly affects BDNF levels in the VMH and disrupts normal hypothalamic function.
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Affiliation(s)
- Phu V Tran
- Department of Physiology, University of California, San Francisco, San Francisco, California 94143, USA
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16
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King BM. The rise, fall, and resurrection of the ventromedial hypothalamus in the regulation of feeding behavior and body weight. Physiol Behav 2006; 87:221-44. [PMID: 16412483 DOI: 10.1016/j.physbeh.2005.10.007] [Citation(s) in RCA: 335] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2005] [Accepted: 10/14/2005] [Indexed: 10/25/2022]
Abstract
Early researchers found that lesions of the ventromedial hypothalamus (VMH) resulted in hyperphagia and obesity in a variety of species including humans, which led them to designate the VMH as the brain's "satiety center." Many researchers later dismissed a role for the VMH in feeding behavior when Gold claimed that lesions restricted to the VMH did not result in overeating and that obesity was observed only with lesions or knife cuts that extended beyond the borders of the VMH and damaged or severed the ventral noradrenergic bundle (VNAB) or paraventricular nucleus (PVN). However, anatomical studies done both before and after Gold's study did not replicate his results with lesions, and in nearly every published direct comparison of VMH lesions vs. PVN or VNAB lesions, the group with VMH lesions ate substantially more food and gained twice as much weight. Several other important differences have also been found between VMH and both PVN and VNAB lesion-induced obesity. Concerns regarding (a) motivation to work for food and (b) the effects of nonirritative lesions have also been addressed and answered in many studies. Lesion studies with weanling rats and adult pair-tube-fed rats, as well as recent studies of knockout mice deficient in the orphan nuclear receptor steroidogenic factor 1, indicate that VMH lesion-induced obesity is in large part a metabolic obesity (due to autonomic nervous system disorders) independent of hyperphagia. However, there is ample evidence that the VMH also plays a primary role in feeding behavior. Neuroimaging studies in humans have shown a marked increase in activity in the area of the VMH during feeding. The VMH has a large population of glucoresponsive neurons that dynamically respond to blood glucose levels and numerous histamine, dopamine, serotonin, and GABA neurons that respond to feeding-related stimuli. Recent studies have implicated melanocortins in the VMH regulation of feeding behavior: food intake decreases when arcuate nucleus pro-opiomelanocortin (POMC) neurons activate VMH brain-derived neurotrophic factor (BDNF) neurons. Moderate hyperphagia and obesity have also been observed in female rats with damage to the efferent projections from the posterodorsal amygdala to the VMH. Hypothalamic obesity can result from damage to either the POMC or BDNF neurons. The concept of hypothalamic feeding and satiety centers is outdated and unnecessary, and progress in understanding hypothalamic mechanisms of feeding behavior will be achieved only by appreciating the different types of neural and blood-borne information received by the various nuclei, and then attempting to determine how this information is integrated to obtain a balance between energy intake and energy output.
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Affiliation(s)
- Bruce M King
- Department of Psychology, University of New Orleans, New Orleans, LA 70148, USA.
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17
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Vicentic A, Dominguez G, Hunter RG, Philpot K, Wilson M, Kuhar MJ. Cocaine- and amphetamine-regulated transcript peptide levels in blood exhibit a diurnal rhythm: regulation by glucocorticoids. Endocrinology 2004; 145:4119-24. [PMID: 15155577 DOI: 10.1210/en.2003-1648] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cocaine- and amphetamine-regulated transcript (CART) peptides are novel neurotransmitters that are implicated in several physiological functions such as control of feeding behavior, drug reward, sensory processing, stress, and development. Although a majority of studies have examined the role of CART in the brain, less is known about its function in the periphery. Therefore, the goals of this study were to examine the levels and species of CART peptides in blood, to determine whether they undergo diurnal rhythms, and to elucidate their sources and regulatory factors. RIA showed that CART peptides are present in the blood of rats and monkeys and that they exhibit a diurnal variation. Western blotting confirmed the pattern of diurnal variation in rats and, additionally, showed that CART immunoreactivity was due to a single predominant fragment with an apparent molecular weight in the range of the active CART 55-102 peptide. Adrenalectomy caused a 70% reduction in CART peptide levels in rat blood, and this was reversed by corticosterone replacement. CART levels paralleled glucocorticoid levels in rat and monkey blood. Control of CART levels by corticosterone suggests the possibility that CART peptides in blood may be influenced by hypothalamic-pituitary-adrenal interactions and that they may play a role in glucocorticoid-related processes such as stress.
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Affiliation(s)
- A Vicentic
- Yerkes National Primate Research Center of Emory University, 954 Gatewood Road NE, Atlanta, Georgia 30329, USA.
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18
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Gonzalez-Bono E, Rohleder N, Hellhammer DH, Salvador A, Kirschbaum C. Glucose but not protein or fat load amplifies the cortisol response to psychosocial stress. Horm Behav 2002; 41:328-33. [PMID: 11971667 DOI: 10.1006/hbeh.2002.1766] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously reported that glucose intake amplifies cortisol response to psychosocial stress and smoking in healthy young men, while low blood glucose levels prevented the stress-induced activation of the hypothalamus pituitary adrenal (HPA) axis. However, it remains unknown whether this modulation is specific for glucose load or a more common effect of energy availability. To elucidate this question, 37 healthy men, who fasted for at least 8 h before the experiment, were randomly assigned to four experimental groups, who received glucose (n = 8), protein (n = 10), fat (n = 10), and water (n = 9), one h before their exposure to the Trier Social Stress Test (TSST). Blood glucose levels were measured at baseline and following stress, while salivary cortisol was assessed repeatedly measured before after the TSST. The results show that both absolute cortisol levels and net cortisol increase were greater in the glucose group in comparison to the other groups (F(3,33) = 3.00, P < 0.05 and F(3,33) = 3.08, P < 0.05, respectively. No group differences were observed with respect to perceived stress and mood. Furthermore, the cortisol response was positively correlated with blood glucose changes (r = 0.49, P < 0.002). In conclusion, the results suggest a central mechanism responsible for regulation of energy balance and HPA axis activation, rather than peripheral mechanisms. We thus recommend controlling for blood glucose levels when studying HPA axis responsiveness.
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Kokavec A, Crowe SF. The effect of a moderate level of white wine consumption on the hypothalamic-pituitary-adrenal axis before and after a meal. Pharmacol Biochem Behav 2001; 70:243-50. [PMID: 11701194 DOI: 10.1016/s0091-3057(01)00606-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The nutritional status of the individual at the time of alcohol consumption may mediate the rate of alcohol absorption and metabolism, thus influencing the systemic effect of alcohol on the body. The aim in the present investigation was to assess the effect of moderate white wine consumption on the hypothalamic-pituitary-adrenal (HPA) axis under variable nutritional conditions. Seven males aged between 19 and 22 years participated in all aspects of the current investigation. The experimental procedure for the fasting trial required participants to ingest either 4 standard units of alcohol (40 g) or the equivalent amount of placebo over a 135-min period before consuming food for 45 min. Alternatively, in the feeding trial, food was consumed for 45 min prior to participants ingesting either 4 standard units of alcohol (40 g) or the equivalent amount of placebo over a 135-min period. Blood alcohol, salivary cortisol, and salivary dehydroepiandrosterone sulfate (DHEAS) levels were assessed at 45-min intervals during the 180-min experimental periods. The results demonstrated a significant alcohol-induced decrease in salivary cortisol irrespective of nutritional status and a significant decrease in salivary DHEAS when alcohol is consumed alone under fasting conditions only. It was concluded that moderate white wine consumption may promote a transient alteration in the functioning of the HPA axis.
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Affiliation(s)
- A Kokavec
- School of Psychological Science, La Trobe University, Bundoora 3083, Australia
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20
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Buijs RM, Chun SJ, Niijima A, Romijn HJ, Nagai K. Parasympathetic and sympathetic control of the pancreas: a role for the suprachiasmatic nucleus and other hypothalamic centers that are involved in the regulation of food intake. J Comp Neurol 2001; 431:405-23. [PMID: 11223811 DOI: 10.1002/1096-9861(20010319)431:4<405::aid-cne1079>3.0.co;2-d] [Citation(s) in RCA: 236] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
To reveal brain regions and transmitter systems involved in control of pancreatic hormone secretion, specific vagal and sympathetic denervation were combined with injection of a retrograde transsynaptic tracer, pseudorabies virus (PRV), into the pancreas. After sympathetic or vagal transsection first-order neurons were revealed in the dorsal motor nucleus of the vagus (DMV) or in preganglionic spinal cord neurons (SPN), respectively. Careful timing of the survival of the animals allowed the detection of cell groups in immediate control of these DMV or SPN neurons. A far larger number of cell groups is involved in the control of DMV than of SPN neurons. Examples are given of a high level of interaction between the sympathetic and parasympathetic nervous system. Several cell groups project to both branches of the autonomic nervous system, sometimes even the same neurotransmitter is used, e.g., oxytocin neurons in the paraventricular nucleus and melanin-concentrating hormone and orexin neurons in the lateral hypothalamus project to both the DMV and SPN neurons. Moreover, the appearance of third-order neurons located in the sympathetic SPN after complete sympathectomy and in the DMV after complete vagotomy illustrates the possibility that motor neurons of the sympathetic and parasympathetic system may exchange information by means of interneurons. The presence of second-order neurons in prefrontal, gustatory, and piriform cortex may provide an anatomic basis for the involvement of these cortices in the cephalic insulin response. The observation that second-order neurons in both vagal and sympathetic control of the pancreas contain neuropeptides that are known to play a role in food intake indicates a direct association between behavioral and autonomic functions. Finally, the observation of third-order neurons in the suprachiasmatic nucleus and ventromedial hypothalamus shows the modulatory action of the time of the day and metabolic state, respectively.
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Affiliation(s)
- R M Buijs
- Netherlands Institute for Brain Research, Meibergdreef 33, Amsterdam 1105 AZ, The Netherlands.
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21
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Bell ME, Bhatnagar S, Akana SF, Choi S, Dallman MF. Disruption of arcuate/paraventricular nucleus connections changes body energy balance and response to acute stress. J Neurosci 2000; 20:6707-13. [PMID: 10964976 PMCID: PMC6772961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/1999] [Accepted: 06/15/2000] [Indexed: 02/17/2023] Open
Abstract
The mediobasal hypothalamus regulates functions necessary for survival, including body energy balance and adaptation to stress. The purpose of this experiment was to determine the contribution of the arcuate nucleus (ARC) in controlling these two functions by the paraventricular nucleus (PVN). Circular, horizontal cuts (1.0 mm radius) were placed immediately above the anterior ARC to sever afferents to the PVN. In shams the knife was lowered to the same coordinates but was not rotated. Food intake and body weight were monitored twice daily, at the beginning and end of the light cycle, for 1 week. On the final day the animals were restrained for 30 min. Lesioned animals had increased food intake in light and dark periods, higher weight gain per day, and more body fat as compared with shams. There was no difference in caloric efficiency. Unlike shams, lesioned rats had no predictable relationship between plasma insulin and leptin. Plasma ACTH was increased at 0 min in lesioned rats but was decreased 15 and 30 min after restraint as compared with shams. There was no difference in plasma corticosterone. Immunostaining revealed that alpha-melanocortin (alphaMSH) and neuropeptide Y (NPY) accumulated below the cuts, and both were decreased in PVN. Food intake and body weight were correlated negatively to alphaMSH, but not NPY in PVN. There was no difference in proopiomelanocortin (POMC) mRNA, but NPY mRNA was reduced in the ARC of lesioned animals. We conclude that ARC controls body energy balance in unstressed rats, possibly by alphaMSH input to PVN, and that ARC also is necessary for PVN regulation of ACTH.
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Affiliation(s)
- M E Bell
- Department of Physiology, University of California, San Francisco, San Francisco, California 94143, USA
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22
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Abstract
The discovery of leptin has enhanced understanding of the interrelationship between adipose energy stores and neuronal circuits in the brain involved in energy balance and regulation of the neuroendocrine axis. Leptin levels are dependent on the status of fat stores as well as changes in energy balance as a result of fasting and overfeeding. Although leptin was initially thought to serve mainly as an anti-satiety hormone, recent studies have shown that it mediates the adaptation to fasting. Furthermore, leptin has been implicated in the regulation of the reproductive, thyroid, growth hormone, and adrenal axes, independent of its role in energy balance. Although it is widely known that leptin acts on hypothalamic neuronal targets to regulate energy balance and neuroendocrine function, the specific neuronal populations mediating leptin action on feeding behavior and autonomic and neuroendocrine function are not well understood. In this review, we have discussed how leptin engages arcuate hypothalamic neurons expressing putative orexigenic peptides, e.g., neuropeptide Y and agouti-regulated peptide, and anorexigenic peptides, e.g., pro-opiomelanocortin (precursor of alpha-melanocyte-stimulating hormone) and cocaine- and amphetamine-regulated transcript. We show that leptin's effects on energy balance and the neuroendocrine axis are mediated by projections to other hypothalamic nuclei, e.g., paraventricular, lateral, and perifornical areas, as well as other sites in the brainstem, spinal cord, and cortical and subcortical regions.
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Affiliation(s)
- R S Ahima
- Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, 19104, USA.
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Dube MG, Kalra SP, Kalra PS. Hypothalamic galanin is up-regulated during hyperphagia and increased body weight gain induced by disruption of signaling in the ventromedial nucleus. Peptides 2000; 21:519-26. [PMID: 10822107 DOI: 10.1016/s0196-9781(00)00172-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Disruption of signaling in the ventromedial nucleus (VMN) by colchicine (COL) produces transient (4 days) hyperphagia and weight gain. Microinjection of galanin into various hypothalamic sites stimulates feeding, so we tested the hypothesis that galanin is up-regulated in COL-treated rats by analyzing galanin concentrations in micropunched hypothalamic sites. Galanin was increased in the paraventricular nucleus on Days 1 through 4 after COL-injection. Galanin was also elevated in three other hypothalamic sites, the dorsomedial nucleus, lateral hypothalamic area, and perifornical hypothalamus, on Days 2-4 and in the lateral preoptic area, on Day 1 only. In the median eminence-arcuate nucleus and amygdala an initial decrease on Day 1 was followed by a then progressive increase through Day 4. These increases occurred despite marked elevations in blood insulin and leptin, hormones known to suppress hypothalamic galanin. When COL- or saline-treated rats were injected intracerebroventricularly with galanin, it stimulated feeding further in the hyperphagic COL-treated rats, but the relative response over basal consumption was similar in both COL-treated and control rats. These results in VMN disrupted rats suggest that neurochemical rearrangements, including increased availability of galanin, may contribute to the hyperphagia and increased weight gain; additionally, it seems that neurons in the VMN normally exert a restraint on galanin signaling.
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Affiliation(s)
- M G Dube
- Department of Physiology, University of Florida College of Medicine, University of Florida Brain Institute, Gainesville, FL 32610, USA.
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Choi S, Sparks R, Clay M, Dallman MF. Rats with hypothalamic obesity are insensitive to central leptin injections. Endocrinology 1999; 140:4426-33. [PMID: 10499495 DOI: 10.1210/endo.140.10.7064] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Genetically determined obesities, involving leptin- and melanocortin-signaling pathways, have focused attention on the four medial hypothalamic nuclei as primary sources of feeding- and metabolically-based obesity. All four medial cell groups contain leptin receptors. To determine which of these cell groups normally mediates the effects of leptin on food intake and body weight gain, we injected colchicine bilaterally into each nucleus and determined the pathophysiological effects of disruption and responsivity to leptin injected intracerebroventricularly. Intracerebroventricular injections of leptin in sham-lesioned rats decreased food intake during the dark period, but not during the light period. Lesions of the arcuate (ARC), paraventricular (PVN), and ventromedial (VMN) nuclei all resulted in leptin insensitivity; by contrast, lesions of the dorsomedial nuclei (DMN) augmented sensitivity to leptin on feeding and body weight gain. Although rats with ARC and PVN lesions were obese, they were still capable of reducing caloric efficiency over the 5 days of study and increasing uncoupling protein content in interscapular brown adipose tissue. Caloric efficiency and uncoupling protein content were unchanged in rats with VMN and DMN lesions. Finally, the slope of the relationship between leptin and mesenteric white adipose tissue was increased in rats with VMN lesions and abolished in rats with ARC lesions. Thus, lesions of the ARC, PVN, and VMN produced obesity via separate pathways. We conclude that the medial hypothalamic cell groups, each with a different role in energy balance, are all necessary for normal leptin responsiveness.
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Affiliation(s)
- S Choi
- Department of Physiology, University of California, San Francisco 94143-0444, USA.
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25
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Abstract
Cell groups of the medial hypothalamus are key to the regulation of energy balance. Functional disruption by colchicine injected in the hypothalamic arcuate (ARC), paraventricular (PVN), and ventromedial (VMN) cell groups produced increased food intake and obesity; disruption of the dorsomedial nuclei (DMN) produced decreased food intake. Colchicine in ARC or PVN increased food intake during both light and dark periods and increased cumulative food intake. By contrast, colchicine in VMN increased food intake only during the light, and cumulative food intake was not increased. Both leptin and insulin were elevated in the obese rats. Compared with sham, the slope of regression of leptin on insulin was increased by disruption of PVN and DMN but was not altered by disruption of VMN. ARC disruption abolished the relationship between leptin and insulin. Colchicine injected in the DMN did not cause obesity but altered feeding and the normal relationship between leptin, fat, and insulin, suggesting that blockade of signals, for example, from the lateral hypothalamus to DMN may disinhibit the normal medial hypothalamic drive to decrease energy stores. Changes in caloric efficiency with time after colchicine injections suggest that rats with both ARC and PVN disruption respond to signals of obesity, whereas rats with VMN disruption do not. These studies distinguish among functions in the four medial hypothalamic nuclei and suggest that interactions among them normally serve to regulate energy balance through alterations in food acquisition and storage.
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Affiliation(s)
- S Choi
- Department of Physiology, University of California San Francisco, 94143-0444, USA.
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Eghbal-Ahmadi M, Avishai-Eliner S, Hatalski CG, Baram TZ. Differential regulation of the expression of corticotropin-releasing factor receptor type 2 (CRF2) in hypothalamus and amygdala of the immature rat by sensory input and food intake. J Neurosci 1999; 19:3982-91. [PMID: 10234028 PMCID: PMC3139461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
The physiological consequences of activating corticotropin-releasing factor receptor type 2 (CRF2) are not fully understood. The neuroanatomic distribution of this CRF receptor family member is consistent with roles in mediating the actions of CRF and similar ligands on food intake control and integrative aspects of stress-related behaviors. However, CRF2 expression in the adult rat is not influenced by stress, corticosterone (CORT), or food intake. In immature rat we have demonstrated striking downregulation of CRF2mRNA in hypothalamic ventromedial nucleus (VMH) after 24 hr of maternal deprivation, a paradigm consisting of both physiological/psychological stress and food deprivation. The current study aimed to distinguish which element or elements of maternal deprivation govern CRF2mRNA expression by isolating the effects of food intake and discrete maternal sensory cues on CRF2mRNA levels in VMH and in reciprocally communicating amygdala nuclei. In maternally deprived pups, CRF2mRNA levels in VMH and basomedial (BMA) and medial (MEA) amygdala nuclei were 62, 72, and 102% of control levels, respectively. Sensory inputs of grooming and handling as well as of the pups' own suckling activity-but not food intake-fully restored CRF2mRNA expression in VMH. In contrast, all manipulations tended to increase CRF2mRNA levels in BMA of maternally deprived rats, and surrogate grooming increased CRF2mRNA expression significantly above that of nondeprived controls. CRF2mRNA expression was not influenced significantly by plasma adrenocorticotropic hormone (ACTH) and CORT levels. Thus, in the immature rat, (1) CRF2 expression is regulated differentially in hypothalamic and amygdala regions, and (2) CRF2mRNA levels in VMH are governed primarily by maternal or suckling-derived sensory input rather than food intake or peripheral stress hormones. These findings indicate a region-specific regulation of CRF2mRNA, supporting the participation of the receptor in neurochemically defined circuits integrating sensory cues to influence specific behavioral and visceral functions.
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Affiliation(s)
- M Eghbal-Ahmadi
- Departments of Anatomy and Neurobiology and Pediatrics, University of California at Irvine, Irvine, California 92697-4475, USA
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Pu S, Dube MG, Edwards TG, Kalra SP, Kalra PS. Disruption of neural signaling within the hypothalamic ventromedial nucleus upregulates galanin gene expression in association with hyperphagia: an in situ hybridization analysis. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1999; 64:85-91. [PMID: 9889330 DOI: 10.1016/s0169-328x(98)00309-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Hypothalamic neuropeptides play critical roles in the regulation of appetite and body weight. We recently reported that disruption of neural signaling in the ventromedial nucleus (VMN) by microinjection of the neurotoxin, colchicine (COL), produced transient hyperphagia with attendant body weight gain lasting for 4 days. The neural mechanism(s) underlying this temporary shift in energy homeostasis is still unknown. Galanin (GAL) is produced in several hypothalamic nuclei and since microinjection of GAL into these sites stimulates feeding, we tested the hypothesis that galaninergic signaling is upregulated in COL-treated rats. COL (4 microgram in 0.5 microliter saline) or saline alone was microinjected into the VMN of adult male rats and GAL mRNA was evaluated in the basal hypothalamus by ribonuclease protection assay on day 1, day 2 and day 4 after injection. Whereas in saline-treated rats body weight and GAL mRNA remained unaffected, they were significantly increased in COL-injected rats through the period of observation. To identify the specific neuronal subpopulations involved, GAL mRNA levels were analyzed in feeding-related hypothalamic nuclei using semiquantitative in situ hybridization histochemistry on day 4 after microinjection of COL or saline into the VMN. In COL-treated rats, GAL mRNA levels increased dramatically over controls in the supraoptic nucleus, paraventricular nucleus (PVN), dorsomedial nucleus (DMN), arcuate nucleus (ARC) and lateral hypothalamic area (LHA); no significant change was observed in the central nucleus of amygdala. These results indicated that disruption of neurotransmission in the VMN upregulated GAL gene expression in those hypothalamic sites (PVN, DMN, LHA and ARC) that are implicated in regulation of feeding, and since GAL stimulates feeding, this neurochemical rearrangement may contribute to the over-eating in these animals. These results also suggest that, normally, neurons in the VMN may suppress GAL neurotransmission in feeding-regulating hypothalamic neural circuits.
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Affiliation(s)
- S Pu
- Department of Neuroscience, University of Florida College of Medicine, University of Florida Brain Institute, PO Box 100244, Gainesville, FL 32610, USA.
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29
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Perret G, Schluger JH, Unterwald EM, Kreuter J, Ho A, Kreek MJ. Downregulation of 5-HT1A receptors in rat hypothalamus and dentate gyrus after "binge" pattern cocaine administration. Synapse 1998; 30:166-71. [PMID: 9723786 DOI: 10.1002/(sici)1098-2396(199810)30:2<166::aid-syn6>3.0.co;2-a] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The effect of chronic cocaine exposure on the central serotonergic system in the rat was investigated using a selective 5-HT1A receptor agonist, [3H]8-hydroxy-2-(di-N-propylamino) tetralin (8-OH-DPAT), and a 5-HT2A receptor antagonist, [3H]ketanserin, as tritiated ligands in a quantitative autoradiography study. Rats were administered cocaine in a "binge" pattern, 15 mg/kg/injection, three times a day, at 1-h intervals for 14 days to mimic the pattern often seen in human cocaine addicts. A significant decrease in the binding of [3H]8-OH-DPAT was found in the ventromedial hypothalamus (P < 0.001) and the dorsal dentate gyrus (P < 0.01) in rats administered cocaine as compared with rats injected with saline. No significant difference in the binding of [3H]ketanserin was found in frontal, parietal, agranular insular, and piriform cortices, caudate-putamen, olfactory tubercle, nucleus accumbens, thalamus, septohippocampal nucleus, and claustrum. Several studies have shown that 5-HT1A receptor agonists have antidepressant properties. Other studies, in animal models, have shown that 5-HT1A receptor agonists stimulate the hypothalamic-pituitary-adrenal axis, which is of interest, since chronic activation of this axis has been related to anxiety and depression. Our data show that the 5-HT1A component of the serotonergic system is altered following chronic "binge" pattern cocaine administration in an animal model and may be related to changes in the HPA axis and behavior.
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Affiliation(s)
- G Perret
- The Rockefeller University, New York, New York 10021, USA
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30
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Elmquist JK, Maratos-Flier E, Saper CB, Flier JS. Unraveling the central nervous system pathways underlying responses to leptin. Nat Neurosci 1998; 1:445-50. [PMID: 10196541 DOI: 10.1038/2164] [Citation(s) in RCA: 405] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Here we summarize recent progress in the biology of leptin, concentrating on its central nervous system (CNS) actions. The product of the ob gene, leptin is a circulating hormone produced by white adipose tissue that has potent effects on feeding behavior, thermogenesis and neuroendocrine responses. Leptin regulates energy homeostasis, as its absence in rodents and humans causes severe obesity. We consider the physiological mechanisms underlying leptin action, along with several novel hypothalamic neuropeptides that affect food intake and body weight. The molecular causes of several other obesity syndromes are discussed to illuminate how the CNS regulates body weight. We describe neural circuits that are downstream of leptin receptors and propose a model linking populations of leptin-responsive neurons with effector neurons underlying leptin's endocrine, autonomic and behavioral effects.
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Affiliation(s)
- J K Elmquist
- Department of Medicine, Division of Endocrinology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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31
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Ogilvie K, Rivier C. The intracerebroventricular injection of interleukin-1beta blunts the testosterone response to human chorionic gonadotropin: role of prostaglandin- and adrenergic-dependent pathways. Endocrinology 1998; 139:3088-95. [PMID: 9645680 DOI: 10.1210/endo.139.7.6090] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The present work extends our previous report that the intracerebroventricular (i.c.v.) injection of interleukin-1beta(IL-1beta, 80 ng) significantly blunted the testosterone response to 1 U/kg human CG (hCG), an effect that we attributed to the stimulation of inhibitory pathways connecting the hypothalamus to the testes. Systemic blockade of prostaglandin-dependent pathways with ibuprofen (alpha-methyl-4-[2-methylpropyl]benzeneacetic acid; sodium salt), which did not, in itself, alter the stimulatory effect of hCG on testosterone release in control rats, modestly, but significantly (P < 0.05) reversed the inhibitory influence of IL-1beta. In contrast, blockade of brain receptors for CRF was unable to alter the effect of IL-1beta, as were lesions of the ventromedial hypothalamic nucleus, a brain area implicated in the control of ovarian function. Blockade of beta-adrenergic receptors significantly prevented the decrease in testicular responsiveness induced by the i.c.v. injection of IL-1beta. Finally, the central injection of the beta-adrenergic agonist isoproterenol, as well as that of norepinephrine, mimicked the ability of icv IL-1beta to blunt testicular secretory activity and produced a marked (P < 0.01) decrease in the response to hCG within 5 min of their administration. We propose that the explanation that best fits our findings is that the i.c.v. injection of IL-1beta activates a neural, catecholamine-dependent pathway that connects the brain and the testes independently of the pituitary.
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Affiliation(s)
- K Ogilvie
- Ligand Pharmaceuticals, Department of Pharmacology, San Diego, California 92121, USA
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32
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Choi S, Wong LS, Yamat C, Dallman MF. Hypothalamic ventromedial nuclei amplify circadian rhythms: do they contain a food-entrained endogenous oscillator? J Neurosci 1998; 18:3843-52. [PMID: 9570813 PMCID: PMC6793147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/1997] [Revised: 02/20/1998] [Accepted: 02/25/1998] [Indexed: 02/07/2023] Open
Abstract
Several endogenous oscillators determine circadian rhythms. One, light-entrained, is in the suprachiasmatic nuclei (SCN), the others, food-entrained, are in unknown sites. To determine how the hypothalamic ventromedial nuclei (VMN) and feeding affect rhythms, we compared nocturnally active rats fed either ad libitum or for 2 hr/d during light [restricted feeding (RF)] and either with or without colchicine-induced disruption of VMN. We measured rhythms in temperature, locomotor activity, feeding, drinking, corticosterone, and the numbers of cells expressing c-Fos in light/dark in hypothalamic nuclei, the suprachiasmatic nuclei, and two major SCN targets, the subparaventricular zone (sPVNz) and paraventricular thalamus (pvTHAL). c-Fos cells were always light > dark in SCN, whereas the VMN and sPVNz lacked light/dark differences except after RF and RF plus VMN disruption, respectively. Controls fed ad libitum had high-amplitude rhythms and, generally, c-Fos cells dark > light. In RF controls, a c-Fos pattern dark > light occurred in VMN; generally, c-Fos cell numbers increased elsewhere maintaining dark > light. By contrast, levels of corticosterone peaked before food. In rats fed ad libitum, VMN with colchicine markedly reduced rhythm amplitudes, not phase. c-Fos patterns were abolished except in pvTHAL and SCN. In RF, VMN disruption blocked corticosterone and light/dark c-Fos patterns in all nuclei but produced a pattern in the sPVNz like SCN. We conclude that VMN amplify rhythmic output from the SCN, and the RF-induced rhythm in VMN enhances c-Fos activity driven by the SCN. The VMN may contain a food-entrained oscillator, and the sPVNz may integrate output from several oscillators.
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Affiliation(s)
- S Choi
- Department of Physiology, University of California San Francisco, San Francisco, California 94143-0444, USA
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33
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Eghbal-Ahmadi M, Hatalski C, Lovenberg T, Avishai-Eliner S, Chalmers D, Baram T. The developmental profile of the corticotropin releasing factor receptor (CRF2) in rat brain predicts distinct age-specific functions. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1998; 107:81-90. [PMID: 9602071 PMCID: PMC3387927 DOI: 10.1016/s0165-3806(98)00002-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Corticotropin releasing factor (CRF) activates two known receptor types, CRF1, and CRF2. In the adult rat brain, CRF2 has a distinct distribution pattern, suggesting that it may mediate functions exclusive of CRF1. The goal of this study was to determine the age-dependent distribution of CRF2-messenger RNA (CRF2-mRNA) in the rat brain. Brains from rats sacrificed under stress-free conditions on fetal days (F) 15, 16, 17 and 19, and postnatal days 1, 3, 5, 7, 9, 12, 15, 25, 49, and 90 (adult) were analyzed using semiquantitative in situ hybridization histochemistry. The onset and distribution of CRF2-mRNA in the developing rat brain revealed important differences from the adult expression pattern: earliest expression of CRF2-mRNA was observed in the ventromedial hypothalamus (VMH) on F16. High levels of CRF2-mRNA were present in the fronto-parietal cortex in the fetal and early postnatal brain but not later. Conversely, no CRF2-mRNA was detectable in the ventroposterior (lateral and medial) thalamic nuclei prior to postnatal day 7. Distinct developmental profiles of CRF2-mRNA were also observed in the lateral septum, medial, basal and cortical amygdala nuclei, and in several hippocampal fields. In conclusion, CRF2 is expressed in the hypothalamus on F16, prior to the detection of CRF itself in the paraventricular nucleus. The differential levels and distributions of CRF2-mRNA in hypothalamic and limbic brain regions indicate a precise regulation of this receptor's expression during development, as shown for CRF1. Regulation of the levels of CRF2 may modulate the effects of CRF (and related ligands) on target neurons, consistent with differential maturation of the functions mediated by this receptor.
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Affiliation(s)
- M. Eghbal-Ahmadi
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, USA
| | - C.G. Hatalski
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, USA
| | | | - S. Avishai-Eliner
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, USA
| | | | - T.Z. Baram
- Department of Anatomy and Neurobiology, University of California, Irvine, CA, USA
- Department of Pediatrics, University of California, Irvine, CA, USA
- Corresponding author. Med. Sci. I, 4475, University of California, Irvine, CA 92697-4475, USA. Fax: +1-714-824-1106;
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Manzanares J, Corchero J, Romero J, Fernandez-Ruiz JJ, Ramos JA, Fuentes JA. Chronic administration of cannabinoids regulates proenkephalin mRNA levels in selected regions of the rat brain. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1998; 55:126-32. [PMID: 9645967 DOI: 10.1016/s0169-328x(97)00371-9] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
This study was designed to examine the interactions between the cannabinoid and enkephalinergic systems in the rat brain. To this aim, we have examined the effects of subchronic (5 days) administration (10 mg.kg-1.day-1; i.p.) of delta 9 -tetrahydrocannabinol (THC) or R-methanandamide (AM356) and chronic (18 days) administration with the synthetic cannabinoid receptor agonist CP-55,940 (1 mg.kg-1.day-1; i.p) on proenkephalin (PENK) mRNA levels in several brain regions of the rat. Twenty micrometer brain sections from striatum, nucleus accumbens, paraventricular nucleus, ventromedial nucleus, periaqueductal grey matter and mammillary nucleus were hybridized with an oligonucleotide probe complementary to PENK using in situ hybridization technique. Subchronic administration of THC or AM356 increased PENK mRNA levels in the ventromedial nucleus of the hypothalamus, (82%) and (39%), in the periaqueductal grey matter, (97%) and (49%), and mammillary nucleus, (43%) and (9%), respectively. In contrast, both drugs were without effect in the striatum and nucleus accumbens. On the other hand, chronic administration of CP-55,940 increased PENK mRNA levels in the striatum (44%), nucleus accumbens (25%), paraventricular (31%) and ventromedial nuclei of the hypothalamus (41%). These results revealed that chronic cannabinoid administration increases opioid gene expression in the rat central nervous system and suggest an interaction between the cannabinoid and enkephalinergic systems that may be part of a molecular integrative response to behavioral and neurochemical alterations that occur in cannabinoid drug abuse.
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Affiliation(s)
- J Manzanares
- Departamento de Farmacología, Facultad de Farmacia, Universidad Complutense de Madrid, Spain.
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Elmquist JK, Ahima RS, Elias CF, Flier JS, Saper CB. Leptin activates distinct projections from the dorsomedial and ventromedial hypothalamic nuclei. Proc Natl Acad Sci U S A 1998; 95:741-6. [PMID: 9435263 PMCID: PMC18491 DOI: 10.1073/pnas.95.2.741] [Citation(s) in RCA: 279] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/1997] [Indexed: 02/05/2023] Open
Abstract
Leptin has profound effects on feeding, metabolism, and neuroendocrine status. Evidence indicates that the hypothalamus coordinates these responses, though the specific brain pathways engaged by leptin remain obscure. The paraventricular nucleus of the hypothalamus (PVH) regulates pituitary gland function and feeding, and innervates autonomic preganglionic neurons, making it a candidate to regulate many of the responses to leptin. The subparaventricular zone, an anterior hypothalamic region receiving dense innervation from the suprachiasmatic nucleus, is thought to integrate circadian and metabolic information. We investigated the distribution of neurons in the rat brain activated by leptin administration that also project to the PVH or the subparaventricular zone by coupling immunohistochemistry for Fos with retrograde transport of cholera toxin-b. Intravenous leptin characteristically activated several cell groups including the ventromedial hypothalamic nucleus, the dorsomedial hypothalamic nucleus (DMH), and the PVH. When tracer injections were centered in the subparaventricular zone, many double-labeled cells were observed in the dorsomedial subdivision of the ventromedial hypothalamic nucleus. This projection may provide an anatomic substrate for integration of metabolic and circadian information to regulate the hypothalamo-pituitary axis. When cholera toxin-b injections were centered in the PVH, many double-labeled cells were found within the caudal DMH. Hence, activation of specific neuroendocrine and autonomic elements of the PVH may be triggered by leptin-activated afferents arising in the DMH. Our results demonstrate that a discrete set of hypothalamic pathways may underlie leptin's autonomic, endocrine, and behavioral effects.
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Affiliation(s)
- J K Elmquist
- Department of Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA.
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36
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Gonzalez MI, Baker BI, Hole DR, Wilson CA. Behavioral effects of neuropeptide E-I (NEI) in the female rat: interactions with alpha-MSH, MCH and dopamine. Peptides 1998; 19:1007-16. [PMID: 9700748 DOI: 10.1016/s0196-9781(98)00045-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The behavioral and neurochemical effects of NEI, and its interaction with alpha-MSH or MCH were investigated in the ventromedial nucleus (VMN) and medial preoptic area (MPOA) in female rats (bilateral administration, 100 ng in 0.5 microliter/side). NEI in the VMN (but not in the MPOA) stimulated exploratory behavior, increased anxiety and reduced dopamine and DOPAC release. The behavioral effects were antagonized by alpha-MSH. NEI stimulated female sexual receptivity in the MPOA. In the VMN, NEI did not have any effect on sexual activity, but partially antagonized the stimulatory effect of MCH. These results show that NEI in the hypothalamus participates in the regulation of behavior, possibly through dopaminergic mediation.
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Affiliation(s)
- M I Gonzalez
- Department Obstetrics and Gynaecology, St. George's Hospital Medical School, London, UK.
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