1
|
Irizarry-Méndez N, Criado-Marrero M, Hernandez A, Colón M, Porter JT. Reducing FKBP51 Expression in the Ventral Hippocampus Decreases Auditory Fear Conditioning in Male Rats. Int J Mol Sci 2024; 25:7097. [PMID: 39000204 PMCID: PMC11241630 DOI: 10.3390/ijms25137097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 06/18/2024] [Accepted: 06/20/2024] [Indexed: 07/16/2024] Open
Abstract
Fear conditioning evokes a physiologic release of glucocorticoids that assists learning. As a cochaperone in the glucocorticoid receptor complex, FKBP51 modulates stress-induced glucocorticoid signaling and may influence conditioned fear responses. This study combines molecular and behavioral approaches to examine whether locally reducing FKBP51 expression in the ventral hippocampus is sufficient to affect fear-related behaviors. We hypothesized that reducing FKBP51 expression in the VH would increase glucocorticoid signaling to alter auditory fear conditioning. Adult male rats were injected with an adeno-associated virus (AAV) vector expressing short hairpin - RNAs (shRNA) targeting FKBP5 into the ventral hippocampus to reduce FKBP5 levels or a control AAV. Infusion of FKBP5-shRNA into the ventral hippocampus decreased auditory fear acquisition and recall. Although animals injected with FKBP5-shRNA showed less freezing during extinction recall, the difference was due to a reduced fear recall rather than improved extinction. Reducing ventral hippocampus FKBP51 did not affect exploratory behavior in either the open field test or the elevated zero maze test but did increase passive behavior in the forced swim test, suggesting that the reduction in auditory fear recall was not due to more active responses to acute stress. Furthermore, lower ventral hippocampus FKBP51 levels did not alter corticosterone release in response to restraint stress, suggesting that the reduced fear recall was not due to lower corticosterone release. Our findings suggest FKBP51 in the ventral hippocampus plays a selective role in modulating fear-learning processes and passive behavioral responses to acute stress rather than hypothalamic-pituitary-adrenal axis reactivity or exploratory responses.
Collapse
Affiliation(s)
- Nashaly Irizarry-Méndez
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce 00716, Puerto Rico; (N.I.-M.)
| | | | - Anixa Hernandez
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce 00716, Puerto Rico; (N.I.-M.)
| | - Maria Colón
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce 00716, Puerto Rico; (N.I.-M.)
| | - James T. Porter
- Department of Basic Sciences, Ponce Research Institute, Ponce Health Sciences University, Ponce 00716, Puerto Rico; (N.I.-M.)
| |
Collapse
|
2
|
Wilkinson MP, Robinson ES, Mellor JR. Analysis of hippocampal synaptic function in a rodent model of early life stress. Wellcome Open Res 2024; 9:300. [PMID: 39221440 PMCID: PMC11362746 DOI: 10.12688/wellcomeopenres.22276.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2024] [Indexed: 09/04/2024] Open
Abstract
Background Early life stress (ELS) is an important risk factor in the aetiology of depression. Developmental glucocorticoid exposure impacts multiple brain regions with the hippocampus being particularly vulnerable. Hippocampal mediated behaviours are dependent upon the ability of neurones to undergo long-term potentiation (LTP), an N-methyl-D-aspartate receptor (NMDAR) mediated process. In this study we investigated the effect of ELS upon hippocampal NMDAR function. Methods Hooded Long-Evans rat pups (n=82) were either undisturbed or maternally separated for 180 minutes per day (MS180) between post-natal day (PND) 1 and PND14. Model validation consisted of sucrose preference (n=18) and novelty supressed feeding (NSFT, n=34) tests alongside assessment of corticosterone (CORT) and paraventricular nucleus (PVN) cFos reactivity to stress and hippocampal neurogenesis (all n=18). AMPA/NMDA ratios (n=19), miniEPSC currents (n=19) and LTP (n=15) were assessed in whole-cell patch clamp experiments in CA1 pyramidal neurones. Results MS180 animals showed increased feeding latency in the NSFT alongside increased overall CORT in the restraint stress experiment and increased PVN cFos expression in males but no changes in neurogenesis or sucrose preference. MS180 was associated with a lower AMPA/NMDA ratio with no change in miniEPSC amplitude or area. There was no difference in short- or long-term potentiation between MS180 and control animals nor were there any changes during the induction protocol. Conclusions The MS180 model showed a behavioural phenotype consistent with previous work. MS180 animals showed increased NMDAR function with preliminary evidence suggesting that this was not concurrent with an increase in LTP.
Collapse
Affiliation(s)
- Matthew P. Wilkinson
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, England, BS8 1TD, UK
- Hello Bio Ltd, Bristol, BS11 0QL, UK
| | - Emma S.J. Robinson
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, England, BS8 1TD, UK
| | - Jack R. Mellor
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, England, BS8 1TD, UK
| |
Collapse
|
3
|
Combined exposure to maternal high-fat diet and neonatal lipopolysaccharide disrupts stress-related signaling but normalizes spatial memory in juvenile rats. Brain Behav Immun 2022; 102:299-311. [PMID: 35259428 DOI: 10.1016/j.bbi.2022.03.003] [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: 10/29/2021] [Revised: 02/27/2022] [Accepted: 03/03/2022] [Indexed: 10/18/2022] Open
Abstract
Both neonatal infections and exposure to maternal obesity are inflammatory stressors in early life linked to increased rates of psychopathologies related to mood and cognition. Epidemiological studies indicate that neonates born to mothers with obesity have a higher likelihood of developing neonatal infections, however effects on offspring physiology and behavior resulting from the combination of these stressors have yet to be investigated. The aim of this study was to explore immediate and persistent phenotypes resulting from neonatal lipopolysaccharide (nLPS) administration in rat offspring born to dams consuming a high-fat diet (HFD). Neural transcript abundance of genes involved with stress regulation and spatial memory were examined alongside related behaviors. At the juvenile age point, unlike offspring exposed to maternal HFD (mHFD) or nLPS alone, offspring with combined exposure to mHFD + nLPS displayed altered transcript abundances of stress-related genes in the ventral hippocampus (HPC) in a manner conducive to potentiating stress responses. For memory-related phenotypes, juveniles exposed to mHFD + nLPS exhibited normalized spatial memory and levels of memory-related gene expression in the dorsal HPC similar to control diet offspring, while control diet + nLPS, and mHFD offspring exhibited reduced levels of memory-related gene expression and impaired spatial memory. These findings suggest that dual exposure to unique inflammatory stressors in early life can disrupt neural stress regulation but normalize spatial memory processes.
Collapse
|
4
|
Gulyaeva NV. Glucocorticoid Regulation of the Glutamatergic
Synapse: Mechanisms of Stress-Dependent Neuroplasticity. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021030091] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
5
|
Renormalizing synapses in sleep: The clock is ticking. Biochem Pharmacol 2021; 191:114533. [PMID: 33771494 DOI: 10.1016/j.bcp.2021.114533] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 12/11/2022]
Abstract
Sleep has been hypothesized to renormalize synapses potentiated in wakefulness. This is proposed to lead to a net reduction in synaptic strength after sleep in brain areas like the cortex and hippocampus. Biological clocks, however, exert independent effects on these synapses that may explain some of the reported differences after wake and sleep. These include changes in synaptic morphology, molecules and efficacy. In this commentary, I discuss why no firm conclusions should be drawn concerning the role of sleep in synaptic renormalization until the role of circadian rhythms are isolated and determined.
Collapse
|
6
|
Norepinephrine and glucocorticoid effects on the brain mechanisms underlying memory accuracy and generalization. Mol Cell Neurosci 2020; 108:103537. [DOI: 10.1016/j.mcn.2020.103537] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 07/31/2020] [Accepted: 08/10/2020] [Indexed: 12/19/2022] Open
|
7
|
|
8
|
Reduced Cortical Excitability, Neuroplasticity, and Salivary Cortisol in 11-13-Year-Old Children Born to Women with Gestational Diabetes Mellitus. EBioMedicine 2018; 31:143-149. [PMID: 29709497 PMCID: PMC6014572 DOI: 10.1016/j.ebiom.2018.04.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/09/2018] [Accepted: 04/09/2018] [Indexed: 01/01/2023] Open
Abstract
Background Children exposed to gestational diabetes mellitus (GDM) in utero are at increased risk of neurodevelopmental difficulties, including autism and impaired motor control. However, the underlying neurophysiology is unknown. Methods Using transcranial magnetic stimulation, we assessed cortical excitability, long-term depression (LTD)-like neuroplasticity in 45 GDM-exposed and 12 control children aged 11–13 years. Data were analysed against salivary cortisol and maternal diabetes severity and treatment (insulin [N = 22] or metformin [N = 23]) during pregnancy. Findings GDM-exposed children had reduced cortical excitability (p = .003), LTD-like neuroplasticity (p = .005), and salivary cortisol (p < .001) when compared with control children. Higher maternal insulin resistance (IR) before and during GDM treatment was associated with a blunted neuroplastic response in children (p = .014) and this was not accounted for by maternal BMI. Additional maternal and neonatal measures, including fasting plasma glucose and inflammatory markers, predicted neurophysiological outcomes. The metformin and insulin treatment groups had similar outcomes. Interpretation These results suggest that GDM can contribute to subtle differences in child neurophysiology, and possibly cortisol secretion, persisting into early adolescence. Importantly, these effects appear to occur during second trimester, before pharmacologic treatment typically commences, and can be predicted by maternal insulin resistance. Therefore, earlier detection and treatment of GDM may be warranted. Metformin appears to be safe for these aspects of neurodevelopment. Children exposed to gestational diabetes (GDM) had lower cortical excitability, measured as higher resting motor thresholds. The GDM group also exhibited smaller LTD-like neuroplastic responses to repetitive brain stimulation. These were associated with lower salivary cortisol and with maternal diabetes severity, especially insulin resistance.
Our results suggest that gestational diabetes, even when detected and treated as per clinical guidelines, has subtle effects on important neurophysiological processes persisting into early adolescence, including neuroplasticity and possibly cortisol secretion. The extent of these effects is related to the severity of maternal diabetes, particularly insulin resistance, during mid pregnancy. These results may aid in understanding how insulin resistance and hyperglycemia affect the developing brain. Further, our results indicate that earlier detection and pharmacologic treatment of gestational diabetes may attenuate or prevent these changes to neurodevelopment, and that maternal metformin treatment does not influence these aspects of development.
Collapse
|
9
|
Sun X, Li X, Pan R, Xu Y, Wang Q, Song M. Total Saikosaponins of Bupleurum yinchowense reduces depressive, anxiety-like behavior and increases synaptic proteins expression in chronic corticosterine-treated mice. Altern Ther Health Med 2018; 18:117. [PMID: 29609584 PMCID: PMC5879550 DOI: 10.1186/s12906-018-2186-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 03/22/2018] [Indexed: 12/22/2022]
Abstract
Background Bupleurum yinchowense Shan et Y. Li is widely used to treat depressive and anxiety disorders for hundreds of years in China. Total saikosaponins (TSS) is the major ingredient of Bupleurum yinchowense. A-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor and subsequent mammalian target of rapamycin (mTOR) signaling is responsible for synaptic maturation and may contribution to the synaptic alteration underlying depression. The aim of the study was to investigate the antidepressant-like and anxiolytic effect of TSS in chronic corticosterone-treated mice. The effect of TSS on synaptic proteins expression and AMPA receptor-mTOR signaling pathway alteration was also evaluated. Methods Dose-response effect of TSS (12.5, 25, 50 mg/kg) was investigated in forced swim test (FST) in ICR male mice. In the chronic corticosterine-treated model, TSS was given intragastrically once a day for 2 weeks and continued through the behavior testing period. Behavior tests and AMPA receptor related signaling pathway were investigated. Results TSS (25 and 50 mg/kg) decreased the immobility time in the FST when compared with the control group. TSS (25 mg/kg) showed antidepressant-like and anxiolytic effects in the chronic corticosterone treatment model in mice. TSS increased hippocampal synaptic proteins (synapsin-1 and postsynaptic density protein 95) expression. Immunohistochemistry analysis showed that TSS significantly increased the synapsin-1 expression in CA3 of hippocampus. TSS also increased hippocampal phosphorylation expression of GluR1 Ser 845 (AMPA receptor subunit) and its downstream regulators extracellular signaling-regulated kinase (ERK), protein kinase B (Akt) and mTOR. Conclusion TSS produces antidepressant-like and anxiolytic effects and increases synaptic proteins expression which may be mediated by induction of AMPA receptor and subsequent mTOR signaling pathway.
Collapse
|
10
|
Osborne DM, O'Leary KE, Fitzgerald DP, George AJ, Vidal MM, Anderson BM, McNay EC. Context-dependent memory following recurrent hypoglycaemia in non-diabetic rats is mediated via glucocorticoid signalling in the dorsal hippocampus. Diabetologia 2017; 60:182-191. [PMID: 27681242 PMCID: PMC5136318 DOI: 10.1007/s00125-016-4114-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 08/23/2016] [Indexed: 11/24/2022]
Abstract
AIMS/HYPOTHESIS Recurrent hypoglycaemia is primarily caused by repeated over-administration of insulin to patients with diabetes. Although cognition is impaired during hypoglycaemia, restoration of euglycaemia after recurrent hypoglycaemia is associated with improved hippocampally mediated memory. Recurrent hypoglycaemia alters glucocorticoid secretion in response to hypoglycaemia; glucocorticoids are well established to regulate hippocampal processes, suggesting a possible mechanism for recurrent hypoglycaemia modulation of subsequent cognition. We tested the hypothesis that glucocorticoids within the dorsal hippocampus might mediate the impact of recurrent hypoglycaemia on hippocampal cognitive processes. METHODS We characterised changes in the dorsal hippocampus at several time points to identify specific mechanisms affected by recurrent hypoglycaemia, using a well-validated 3 day model of recurrent hypoglycaemia either alone or with intrahippocampal delivery of glucocorticoid (mifepristone) and mineralocorticoid (spironolactone) receptor antagonists prior to each hypoglycaemic episode. RESULTS Recurrent hypoglycaemia enhanced learning and also increased hippocampal expression of glucocorticoid receptors, serum/glucocorticoid-regulated kinase 1, cyclic AMP response element binding (CREB) phosphorylation, and plasma membrane levels of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartic acid (NMDA) receptors. Both hippocampus-dependent memory enhancement and the molecular changes were reversed by glucocorticoid receptor antagonist treatment. CONCLUSIONS/INTERPRETATION These results indicate that increased glucocorticoid signalling during recurrent hypoglycaemia produces several changes in the dorsal hippocampus that are conducive to enhanced hippocampus-dependent contextual learning. These changes appear to be adaptive, and in addition to supporting cognition may reduce damage otherwise caused by repeated exposure to severe hypoglycaemia.
Collapse
Affiliation(s)
- Danielle M Osborne
- Behavioural Neuroscience, University at Albany, 1400 Washington Avenue, Albany, NY, 12222, USA
| | | | | | - Alvin J George
- Biological Sciences, University at Albany, Albany, NY, USA
| | | | | | - Ewan C McNay
- Behavioural Neuroscience, University at Albany, 1400 Washington Avenue, Albany, NY, 12222, USA.
- Biological Sciences, University at Albany, Albany, NY, USA.
| |
Collapse
|
11
|
Circadian Regulation of Synaptic Plasticity. BIOLOGY 2016; 5:biology5030031. [PMID: 27420105 PMCID: PMC5037350 DOI: 10.3390/biology5030031] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 06/24/2016] [Accepted: 07/04/2016] [Indexed: 01/02/2023]
Abstract
Circadian rhythms refer to oscillations in biological processes with a period of approximately 24 h. In addition to the sleep/wake cycle, there are circadian rhythms in metabolism, body temperature, hormone output, organ function and gene expression. There is also evidence of circadian rhythms in synaptic plasticity, in some cases driven by a master central clock and in other cases by peripheral clocks. In this article, I review the evidence for circadian influences on synaptic plasticity. I also discuss ways to disentangle the effects of brain state and rhythms on synaptic plasticity.
Collapse
|
12
|
Osanloo N, Sarahian N, Zardooz H, Sahraei H, Sahraei M, Sadeghi B. Effects of Memantine, an NMDA Antagonist, on Metabolic Syndromes in Female NMRI Mice. Basic Clin Neurosci 2015; 6:239-52. [PMID: 26649162 PMCID: PMC4668871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
INTRODUCTION The brain glutamate neurotransmitter system and its NMDA (N-methyl-D-aspartate) receptors in the nucleus accumbens play an important role in the incidence of sensitivity and addiction. The present study examined the inhibitory effect of glutamate NMDA receptors in the nucleus accumbens in response to chronic stress. METHODS After the unilateral and bilateral placement of cannula(e) in the nucleus accumbens, one group of the animals received different doses of intra-accumbens memantine (0.1, 0.5 and 1 μg/mouse) 5 minutes before receiving the electric shock stress at their soles (using a Communication Box) and the other group received intraperitoneal memantine (doses of 0.1, 0.5 and 1mg/kg) 30 minutes before receiving the same shock. Chronic stress increased the animals' weight, plasma corticosterone, food and water intake, but reduced their defecation rates and eating latency. RESULTS The intraperitoneal administration of memantine increased plasma corticosterone, water intake, fecal weight, and eating latency, but had no effect on food intake or weight. The dose and site-dependent intra-accumbens administration of memantine either exacerbated the effects of stress on plasma corticosterone levels, water and food intake, or had no effect on these parameters. Furthermore, the administration of memantine had no effect on animal's weight and inhibited the effects of stress on fecal weight and eating latency. DISCUSSION The inhibition of glutamate NMDA receptors in the nucleus accumbens can inhibit and/or exacerbate the dose and site-dependent effects of chronic stress, and gender plays a significant role in producing this effect too.
Collapse
Affiliation(s)
- Naser Osanloo
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Nahid Sarahian
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran.,Corresponding Author: Nahid Sarahian, PhD, Address: Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Niavaran, Araj St., P.O. Box: 19395-6558, Tehran, Iran., Tel: +98 (21)26127286, E-mail:
| | - Homeira Zardooz
- Department of Physiology, School of Medicine, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran
| | - Hedayat Sahraei
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mohammad Sahraei
- Faculty of Dentistry, Shahid Beheshti University of Medical Sciences and Health Services, Tehran, Iran
| | - Bahareh Sadeghi
- Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| |
Collapse
|
13
|
GABAA receptor-acting neurosteroids: a role in the development and regulation of the stress response. Front Neuroendocrinol 2015; 36:28-48. [PMID: 24929099 PMCID: PMC4349499 DOI: 10.1016/j.yfrne.2014.06.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 05/26/2014] [Accepted: 06/01/2014] [Indexed: 12/22/2022]
Abstract
Regulation of hypothalamic-pituitary-adrenocortical (HPA) axis activity by stress is a fundamental survival mechanism and HPA-dysfunction is implicated in psychiatric disorders. Adverse early life experiences, e.g. poor maternal care, negatively influence brain development and programs an abnormal stress response by encoding long-lasting molecular changes, which may extend to the next generation. How HPA-dysfunction leads to the development of affective disorders is complex, but may involve GABAA receptors (GABAARs), as they curtail stress-induced HPA axis activation. Of particular interest are endogenous neurosteroids that potently modulate the function of GABAARs and exhibit stress-protective properties. Importantly, neurosteroid levels rise rapidly during acute stress, are perturbed in chronic stress and are implicated in the behavioural changes associated with early-life adversity. We will appraise how GABAAR-active neurosteroids may impact on HPA axis development and the orchestration of the stress-evoked response. The significance of these actions will be discussed in the context of stress-associated mood disorders.
Collapse
|
14
|
Abstract
Sleep is hypothesized to play an integral role in brain plasticity. This has traditionally been investigated using behavioral assays. In the last 10-15 years, studies combining sleep measurements with in vitro and in vivo models of synaptic plasticity have provided exciting new insights into how sleep alters synaptic strength. In addition, new theories have been proposed that integrate older ideas about sleep function and recent discoveries in the field of synaptic plasticity. There remain, however, important challenges and unanswered questions. For example, sleep does not appear to have a single effect on synaptic strength. An unbiased review of the literature indicates that the effects of sleep vary widely depending on ontogenetic stage, the type of waking experience (or stimulation protocols) that precede sleep and the type of neuronal synapse under examination. In this review, I discuss these key findings in the context of current theories that posit different roles for sleep in synaptic plasticity.
Collapse
Affiliation(s)
- Marcos G Frank
- Department of Neuroscience, School of Medicine, University of Pennsylvania, 215 Stemmler Hall, 35th and Hamilton Walk, Philadelphia, PA, 19104-6074, USA,
| |
Collapse
|
15
|
Stone TW, Darlington LG. The kynurenine pathway as a therapeutic target in cognitive and neurodegenerative disorders. Br J Pharmacol 2014; 169:1211-27. [PMID: 23647169 DOI: 10.1111/bph.12230] [Citation(s) in RCA: 182] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 04/16/2013] [Accepted: 04/24/2013] [Indexed: 02/06/2023] Open
Abstract
Understanding the neurochemical basis for cognitive function is one of the major goals of neuroscience, with a potential impact on the diagnosis, prevention and treatment of a range of psychiatric and neurological disorders. In this review, the focus will be on a biochemical pathway that remains under-recognized in its implications for brain function, even though it can be responsible for moderating the activity of two neurotransmitters fundamentally involved in cognition - glutamate and acetylcholine. Since this pathway - the kynurenine pathway of tryptophan metabolism - is induced by immunological activation and stress, it also stands in a unique position to mediate the effects of environmental factors on cognition and behaviour. Targeting the pathway for new drug development could, therefore, be of value not only for the treatment of existing psychiatric conditions, but also for preventing the development of cognitive disorders in response to environmental pressures.
Collapse
Affiliation(s)
- Trevor W Stone
- Institute of Neuroscience & Psychology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK.
| | | |
Collapse
|
16
|
Frank MG, Cantera R. Sleep, clocks, and synaptic plasticity. Trends Neurosci 2014; 37:491-501. [PMID: 25087980 PMCID: PMC4152403 DOI: 10.1016/j.tins.2014.06.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 06/12/2014] [Accepted: 06/30/2014] [Indexed: 01/24/2023]
Abstract
Sleep is widely believed to play an essential role in synaptic plasticity. However, the precise mechanisms governing this presumptive function are largely unknown. There is also evidence for independent circadian oscillations in synaptic strength and morphology. Therefore, synaptic changes observed after sleep reflect interactions between state-dependent (e.g., wake versus sleep) and state-independent (circadian) processes. In this review we consider how sleep and biological clocks influence synaptic plasticity. We discuss these findings in the context of current plasticity-based theories of sleep function and propose a new model that integrates circadian and brain-state influences on synaptic plasticity.
Collapse
Affiliation(s)
- Marcos G. Frank
- Department of Neuroscience Perelman School of Medicine University of Pennsylvania Philadelphia, PA 19104
| | - Rafael Cantera
- Zoology Department Stockholm University Stockholm, Sweden Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| |
Collapse
|
17
|
Page KC, Jones EK, Anday EK. Maternal and postweaning high-fat diets disturb hippocampal gene expression, learning, and memory function. Am J Physiol Regul Integr Comp Physiol 2014; 306:R527-37. [DOI: 10.1152/ajpregu.00319.2013] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We tested the hypothesis that excess saturated fat consumption during pregnancy, lactation, and/or postweaning alters the expression of genes mediating hippocampal synaptic efficacy and impairs spatial learning and memory in adulthood. Dams were fed control chow or a diet high in saturated fat before mating, during pregnancy, and into lactation. Offspring were weaned to either standard chow or a diet high in saturated fat. The Morris Water Maze was used to evaluate spatial learning and memory. Open field testing was used to evaluate motor activity. Hippocampal gene expression in adult males was measured using RT-PCR and ELISA. Offspring from high fat-fed dams took longer, swam farther, and faster to try and find the hidden platform during the 5-day learning period. Control offspring consuming standard chow spent the most time in memory quadrant during the probe test. Offspring from high fat-fed dams consuming excess saturated fat spent the least. The levels of mRNA and protein for brain-derived neurotrophic factor and activity-regulated cytoskeletal-associated protein were significantly decreased by maternal diet effects. Nerve growth factor mRNA and protein levels were significantly reduced in response to both maternal and postweaning high-fat diets. Expression levels for the N-methyl-d-aspartate receptor (NMDA) receptor subunit NR2B as well as synaptophysin were significantly decreased in response to both maternal and postweaning diets. Synaptotagmin was significantly increased in offspring from high fat-fed dams. These data support the hypothesis that exposure to excess saturated fat during hippocampal development is associated with complex patterns of gene expression and deficits in learning and memory.
Collapse
Affiliation(s)
- Kathleen C. Page
- Biology Department, Bucknell University, Lewisburg, Pennsylvania; and
| | | | - Endla K. Anday
- Pediatrics, Drexel University College of Medicine, Philadelphia, Pennsylvania
| |
Collapse
|
18
|
Pereiro N, Moyano R, Blanco A, Lafuente A. Regulation of corticosterone secretion is modified by PFOS exposure at different levels of the hypothalamic-pituitary-adrenal axis in adult male rats. Toxicol Lett 2014; 230:252-62. [PMID: 24440345 DOI: 10.1016/j.toxlet.2014.01.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 11/25/2013] [Accepted: 01/02/2014] [Indexed: 01/29/2023]
Abstract
Perfluorooctane sulfonate (PFOS) is a fluorinated compound and a Persistent Organic Pollutant which can disrupt the endocrine system. This work was undertaken to evaluate the possible effects of PFOS exposure on the regulation of corticosterone secretion in adrenal and pituitary glands and at hypothalamic level in adult male rat, and to evaluate the possible morphological alterations induced by PFOS in this endocrine tissue. Adult male rats were orally treated with 0.5, 1.0, 3.0 and 6.0 mg of PFOS/kg/day for 28 days. Corticosterone, adrenocorticotropic hormone (ACTH) and corticotrophin-releasing hormone (CRH) secretion decreased in PFOS-treated rats. After PFOS exposure, relative expression of adrenocorticotropic hormone receptor (ACTHr) and proopiomelanocortin (POMC) genes was increased in adrenal and in pituitary glands, respectively; while relative expression of ACTHr and CRH genes decreased in hypothalamus with the doses of 0.5 and 1.0 mg/kg/day. PFOS treatment increased relative nitric oxide synthase 1 and 2 (NOS1 and NOS2) gene expression in the adrenal gland, and incremented superoxide dismutase activity. PFOS exposure induces a global inhibition of the hypothalamic-pituitary-adrenal (HPA) axis activity, and small morphological changes were observed in adrenal zona fasciculata cells.
Collapse
Affiliation(s)
- N Pereiro
- Laboratory of Toxicology, Faculty of Sciences, University of Vigo, Las Lagunas S/n, 32004 Ourense, Spain
| | - R Moyano
- Department of Pharmacology, Toxicology and Legal and Forensic Medicine, Veterinary Faculty, University of Córdoba, 14071, Córdoba, Spain
| | - A Blanco
- Department of Comparative Pathology, Faculty of Veterinary Medicine, University of Córdoba, 14071 Córdoba, Spain
| | - A Lafuente
- Laboratory of Toxicology, Faculty of Sciences, University of Vigo, Las Lagunas S/n, 32004 Ourense, Spain.
| |
Collapse
|
19
|
Butler TR, Ariwodola OJ, Weiner JL. The impact of social isolation on HPA axis function, anxiety-like behaviors, and ethanol drinking. Front Integr Neurosci 2014; 7:102. [PMID: 24427122 PMCID: PMC3877772 DOI: 10.3389/fnint.2013.00102] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 12/14/2013] [Indexed: 01/27/2023] Open
Abstract
Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is often observed in alcoholics and humans subjected to early life stress, and animal models of ethanol (EtOH) dependence. We examined HPA axis function in a rodent model of early life stress that engenders increases in behavioral and neurobiological risk factors of alcoholism. Long-Evans male rats were group housed (GH) or socially isolated (SI) for 6 weeks during adolescence. We examined the corticosterone (CORT) response to stress with and without dexamethasone (DEX) and anxiety-like behaviors. Following the DEX suppression test and behavioral assays, half of the cohort engaged in 6 weeks of EtOH drinking in a homecage, two-bottle choice intermittent access model. A subset of the cohort was not exposed to EtOH, but was used for electrophysiological measurement of glutamatergic synaptic plasticity in the basolateral amygdala (BLA). Correlational analyses examined relationships between measures of CORT, anxiety-like behaviors, and EtOH intake/preference. With DEX pre-treatment, SI rats failed to suppress CORT in response to an acute stress; GH rats showed a significant suppression. In SI rats, there was a significant negative correlation between baseline CORT and elevated plus maze open arm time, as well as significant positive correlations between baseline CORT and both EtOH intake and preference. No significant relationships between baseline CORT and behavioral measures were observed in GH rats. Glutamatergic plasticity in the BLA was similar in magnitude between GH and SI rats, and was not altered by exogenous application of CORT. These data suggest that HPA axis function is affected by SI, and this is related to antecedent anxiety-like behavior and may predispose for future EtOH self-administration. Relationships between HPA axis function, anxiety, and EtOH measures in SI rats further strengthens the utility of this paradigm in modeling vulnerability for affective disorders and alcoholism.
Collapse
Affiliation(s)
- Tracy R Butler
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine Winston-Salem, NC, USA
| | - Olusegun J Ariwodola
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine Winston-Salem, NC, USA
| | - Jeffrey L Weiner
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine Winston-Salem, NC, USA
| |
Collapse
|
20
|
Prenatal immune activation interacts with stress and corticosterone exposure later in life to modulate N-methyl-D-aspartate receptor synaptic function and plasticity. Int J Neuropsychopharmacol 2013; 16:1835-48. [PMID: 23552018 DOI: 10.1017/s1461145713000229] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Prenatal infection is an environmental risk factor for schizophrenia while later in life, stressful events have been associated with the onset and severity of psychosis. Recent findings on the impact of stress on the N-methyl-d-aspartate receptor (NMDAR), of which hypofunctioning is implicated in schizophrenia, suggest changes in stress-induced regulation of the glutamatergic system may be related to the pathogenesis of schizophrenia. Our study aimed to test whether prenatal immune activation could interact with stress at adolescence to alter NMDAR function. We used offspring from rat dams administered bacterial lipopolysaccharide (LPS) during pregnancy (gestational days 15 and 16), an animal model expressing schizophrenia-related behavioural phenotypes. Using electrophysiological techniques, we investigated effects of stress and the stress hormone corticosterone (Cort) on NMDAR-mediated synaptic function and long-term depression (LTD) in hippocampal CA1 slices from these adolescent (aged 28-39 d) male offspring. In prenatal LPS offspring, NMDAR-mediated synaptic function and LTD were reduced and abolished, respectively, compared to prenatal saline controls. Notably, in vivo stress and in vitro Cort treatment facilitated LTD in slices from prenatal LPS rats but not prenatal saline controls. Finally, Cort enhanced NMDAR-mediated synaptic function in slices from prenatal LPS rats only. We conclude that prenatal immune activation results in NMDAR hypofunction in the hippocampus of adolescent rats but also increases responsiveness of NMDAR-mediated synaptic function and LTD towards stress. Prenatal infection could confer susceptibility to schizophrenia through modification of hippocampal NMDAR function, with hypofunction in resting conditions and heightened responsiveness to stress, thus impacting the development of the disorder.
Collapse
|
21
|
Stress and excitatory synapses: from health to disease. Neuroscience 2013; 248:626-36. [PMID: 23727506 DOI: 10.1016/j.neuroscience.2013.05.043] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 05/01/2013] [Accepted: 05/21/2013] [Indexed: 01/20/2023]
Abstract
Individuals are exposed to stressful events in their daily life. The effects of stress on brain function ranges from highly adaptive to increasing the risk to develop psychopathology. For example, stressful experiences are remembered well which can be seen as a highly appropriate behavioral adaptation. On the other hand, stress is an important risk factor, in susceptible individuals, for depression and anxiety. An important question that remains to be addressed is how stress regulates brain function and what determines the threshold between adaptive and maladaptive responses. Excitatory synapses play a crucial role in synaptic transmission, synaptic plasticity and behavioral adaptation. In this review we discuss how brief and prolonged exposure to stress, in adulthood and early life, regulate the function of these synapses, and how these effects may contribute to behavioral adaptation and psychopathology.
Collapse
|
22
|
Physiological evidence consistent with reduced neuroplasticity in human adolescents born preterm. J Neurosci 2013; 32:16410-6. [PMID: 23152623 DOI: 10.1523/jneurosci.3079-12.2012] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Preterm-born children commonly experience motor, cognitive, and learning difficulties that may be accompanied by altered brain microstructure, connectivity, and neurochemistry. However, the mechanisms linking the altered neurophysiology with the behavioral outcomes are unknown. Here we provide the first physiological evidence that human adolescents born preterm at or before 37 weeks of completed gestation have a significantly reduced capacity for cortical neuroplasticity, the key overall mechanism underlying learning and memory. We examined motor cortex neuroplasticity in three groups of adolescents who were born after gestations of ≤32 completed weeks (early preterm), 33-37 weeks (late preterm), and 38-41 weeks (term) using a noninvasive transcranial magnetic brain stimulation technique to induce long-term depression (LTD)-like neuroplasticity. Compared with term-born adolescents, both early and late preterm adolescents had reduced LTD-like neuroplasticity in response to brain stimulation that was also associated with low salivary cortisol levels. We also compared neuroplasticity in term-born adolescents with that in term-born young adults, finding that the motor cortex retains a relatively enhanced neuroplastic capacity in adolescence. These findings provide a possible mechanistic link between the altered brain physiology of preterm birth and the subsequent associated behavioral deficits, particularly in learning and memory. They also suggest that altered hypothalamic-pituitary-adrenal axis function due to preterm birth may be a significant modulator of this altered neuroplasticity. This latter finding may offer options in the development of possible therapeutic interventions.
Collapse
|
23
|
Maggio N, Krugers HJ, Segal M. Stress and steroid regulation of synaptic transmission: from physiology to pathophysiology. Front Cell Neurosci 2013; 6:69. [PMID: 23335882 PMCID: PMC3547283 DOI: 10.3389/fncel.2012.00069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Accepted: 12/26/2012] [Indexed: 01/31/2023] Open
Affiliation(s)
- Nicola Maggio
- Department of Neurology, The Chaim Sheba Medical Center Tel HaShomer, Israel
| | | | | |
Collapse
|