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Becegato M, Silva RH. Female rodents in behavioral neuroscience: Narrative review on the methodological pitfalls. Physiol Behav 2024; 284:114645. [PMID: 39047942 DOI: 10.1016/j.physbeh.2024.114645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 07/19/2024] [Accepted: 07/22/2024] [Indexed: 07/27/2024]
Abstract
Since the NIH 'Sex as biological variable' policy, the percentage of studies including female subjects have increased largely. Nonetheless, many researchers fail to adequate their protocols to include females. In this narrative review, we aim to discuss the methodological pitfalls of the inclusion of female rodents in behavioral neuroscience. We address three points to consider in studies: the manipulations conducted only in female animals (such as estrous cycle monitoring, ovariectomy, and hormone replacement), the consideration of males as the standard, and biases related to interpretation and publication of the results. In addition, we suggest guidelines and perspectives for the inclusion of females in preclinical research.
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Affiliation(s)
- Marcela Becegato
- Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil
| | - Regina H Silva
- Behavioral Neuroscience Laboratory, Department of Pharmacology, Federal University of São Paulo, São Paulo, Brazil; MaternaCiência, Federal University of São Paulo, São Paulo, Brazil.
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2
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Feetham CH, O'Brien F, Barrett-Jolley R. Ion Channels in the Paraventricular Hypothalamic Nucleus (PVN); Emerging Diversity and Functional Roles. Front Physiol 2018; 9:760. [PMID: 30034342 PMCID: PMC6043726 DOI: 10.3389/fphys.2018.00760] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 05/30/2018] [Indexed: 12/11/2022] Open
Abstract
The paraventricular nucleus of the hypothalamus (PVN) is critical for the regulation of homeostatic function. Although also important for endocrine regulation, it has been referred to as the "autonomic master controller." The emerging consensus is that the PVN is a multifunctional nucleus, with autonomic roles including (but not limited to) coordination of cardiovascular, thermoregulatory, metabolic, circadian and stress responses. However, the cellular mechanisms underlying these multifunctional roles remain poorly understood. Neurones from the PVN project to and can alter the function of sympathetic control regions in the medulla and spinal cord. Dysfunction of sympathetic pre-autonomic neurones (typically hyperactivity) is linked to several diseases including hypertension and heart failure and targeting this region with specific pharmacological or biological agents is a promising area of medical research. However, to facilitate future medical exploitation of the PVN, more detailed models of its neuronal control are required; populated by a greater compliment of constituent ion channels. Whilst the cytoarchitecture, projections and neurotransmitters present in the PVN are reasonably well documented, there have been fewer studies on the expression and interplay of ion channels. In this review we bring together an up to date analysis of PVN ion channel studies and discuss how these channels may interact to control, in particular, the activity of the sympathetic system.
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Affiliation(s)
- Claire H Feetham
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, United Kingdom
| | - Fiona O'Brien
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Richard Barrett-Jolley
- Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
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3
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Bronson DR, Preuss T. Cellular Mechanisms of Cortisol-Induced Changes in Mauthner-Cell Excitability in the Startle Circuit of Goldfish. Front Neural Circuits 2017; 11:68. [PMID: 29033795 PMCID: PMC5625080 DOI: 10.3389/fncir.2017.00068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 09/11/2017] [Indexed: 11/13/2022] Open
Abstract
Predator pressure and olfactory cues (alarm substance) have been shown to modulate Mauthner cell (M-cell) initiated startle escape responses (C-starts) in teleost fish. The regulation of such adaptive responses to potential threats is thought to involve the release of steroid hormones such as cortisol. However, the mechanism by which cortisol may regulate M-cell excitability is not known. Here, we used intrasomatic, in vivo recordings to elucidate the acute effects of cortisol on M-cell membrane properties and sound evoked post-synaptic potentials (PSPs). Cortisol tonically decreased threshold current in the M-cell within 10 min before trending towards baseline excitability over an hour later, which may indicate the involvement of non-genomic mechanisms. Consistently, current ramp injection experiments showed that cortisol increased M-cell input resistance in the depolarizing membrane, i.e., by a voltage-dependent postsynaptic mechanism. Cortisol also increases the magnitude of sound-evoked M-cell PSPs by reducing the efficacy of local feedforward inhibition (FFI). Interestingly, another pre-synaptic inhibitory network mediating prepulse inhibition (PPI) remained unaffected. Together, our results suggest that cortisol rapidly increases M-cell excitability via a post-synaptic effector mechanism, likely a chloride conductance, which, in combination with its dampening effect on FFI, will modulate information processing to reach threshold. Given the central role of the M-cell in initiating startle, these results are consistent with a role of cortisol in mediating the expression of a vital behavior.
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Affiliation(s)
- Daniel R Bronson
- The Graduate Center, City University of New York, New York, NY, United States
| | - Thomas Preuss
- Hunter College, City University of New York, New York, NY, United States
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Nongenomic Glucocorticoid Suppression of a Postsynaptic Potassium Current via Emergent Autocrine Endocannabinoid Signaling in Hypothalamic Neuroendocrine Cells following Chronic Dehydration. eNeuro 2017; 4:eN-NWR-0216-17. [PMID: 28966975 PMCID: PMC5617081 DOI: 10.1523/eneuro.0216-17.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/19/2017] [Accepted: 08/22/2017] [Indexed: 11/21/2022] Open
Abstract
Glucocorticoids rapidly stimulate endocannabinoid synthesis and modulation of synaptic transmission in hypothalamic neuroendocrine cells via a nongenomic signaling mechanism. The endocannabinoid actions are synapse-constrained by astrocyte restriction of extracellular spatial domains. Exogenous cannabinoids have been shown to modulate postsynaptic potassium currents, including the A-type potassium current (IA), in different cell types. The activity of magnocellular neuroendocrine cells is shaped by a prominent IA. We tested for a rapid glucocorticoid modulation of the postsynaptic IK and IA in magnocellular neuroendocrine cells of the hypothalamic paraventricular nucleus (PVN) using whole-cell recordings in rat brain slices. Application of the synthetic glucocorticoid dexamethasone (Dex) had no rapid effect on the IK or IA amplitude, voltage dependence, or kinetics in magnocellular neurons in slices from untreated rats. In magnocellular neurons from salt-loaded rats, however, Dex application caused a rapid suppression of the IA and a depolarizing shift in IA voltage dependence. Exogenously applied endocannabinoids mimicked the rapid Dex modulation of the IA, and CB1 receptor antagonists and agonists blocked and occluded the Dex-induced changes in the IA, respectively, suggesting an endocannabinoid dependence of the rapid glucocorticoid effect. Preincubation of control slices in a gliotoxin resulted in the partial recapitulation of the glucocorticoid-induced rapid suppression of the IA. These findings demonstrate a glucocorticoid suppression of the postsynaptic IA in PVN magnocellular neurons via an autocrine endocannabinoid-dependent mechanism following chronic dehydration, and suggest a possible role for astrocytes in the control of the autocrine endocannabinoid actions.
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Bitencourt RM, Alpár A, Cinquina V, Ferreira SG, Pinheiro BS, Lemos C, Ledent C, Takahashi RN, Sialana FJ, Lubec G, Cunha RA, Harkany T, Köfalvi A. Lack of presynaptic interaction between glucocorticoid and CB1 cannabinoid receptors in GABA- and glutamatergic terminals in the frontal cortex of laboratory rodents. Neurochem Int 2015. [PMID: 26196379 DOI: 10.1016/j.neuint.2015.07.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Corticosteroid and endocannabinoid actions converge on prefrontocortical circuits associated with neuropsychiatric illnesses. Corticosteroids can also modulate forebrain synapses by using endocannabinoid effector systems. Here, we determined whether corticosteroids can modulate transmitter release directly in the frontal cortex and, in doing so, whether they affect presynaptic CB1 cannabinoid receptor- (CB1R) mediated neuromodulation. By Western blotting of purified subcellular fractions of the rat frontal cortex, we found glucocorticoid receptors (GcRs) and CB1Rs enriched in isolated frontocortical nerve terminals (synaptosomes). CB1Rs were predominantly presynaptically located while GcRs showed preference for the post-synaptic fraction. Additional confocal microscopy analysis of cortical and hippocampal regions revealed vesicular GABA transporter-positive and vesicular glutamate transporter 1-positive nerve terminals endowed with CB1R immunoreactivity, apposing GcR-positive post-synaptic compartments. In functional transmitter release assay, corticosteroids, corticosterone (0.1-10 microM) and dexamethasone (0.1-10 microM) did not significantly affect the evoked release of [(3)H]GABA and [(14)C]glutamate in superfused synaptosomes, isolated from both rats and mice. In contrast, the synthetic cannabinoid, WIN55212-2 (1 microM) diminished the release of both [(3)H]GABA and [(14)C]glutamate, evoked with various depolarization paradigms. This effect of WIN55212-2 was abolished by the CB1R neutral antagonist, O-2050 (1 microM), and was absent in the CB1R KO mice. CB2R-selective agonists did not affect the release of either neurotransmitter. The lack of robust presynaptic neuromodulation by corticosteroids was unchanged upon either CB1R activation or genetic inactivation. Altogether, corticosteroids are unlikely to exert direct non-genomic presynaptic neuromodulation in the frontal cortex, but they may do so indirectly, via the stimulation of trans-synaptic endocannabinoid signaling.
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Affiliation(s)
- Rafael M Bitencourt
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal; Laboratory of Psychopharmacology, Dept. Pharmacology, Universidade Federal de Santa Catarina, Florianopolis 88049-900, Brazil
| | - Alán Alpár
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden
| | - Valentina Cinquina
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria; University of Insubria, Via Ravasi, 2, 21100 Varese, Italy
| | - Samira G Ferreira
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal; FMUC, Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Bárbara S Pinheiro
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Cristina Lemos
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal
| | | | - Reinaldo N Takahashi
- Laboratory of Psychopharmacology, Dept. Pharmacology, Universidade Federal de Santa Catarina, Florianopolis 88049-900, Brazil
| | - Fernando J Sialana
- Department of Pediatrics, Medical University of Vienna, Währinger Gürtel 18, A-1090 Vienna, Austria; CeMM Research Center for Molecular Medicine of the Austrian Academy of Science, Lazarettgasse 14, AKH BT 25.3, A-1090 Vienna, Austria
| | - Gert Lubec
- Department of Pediatrics, Medical University of Vienna, Währinger Gürtel 18, A-1090 Vienna, Austria
| | - Rodrigo A Cunha
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal; FMUC, Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Tibor Harkany
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden; Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria
| | - Attila Köfalvi
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra, 3030-789 Coimbra, Portugal.
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Wamsteeker Cusulin JI, Bains JS. Embedded synaptic feedback in the neuroendocrine stress axis. J Neuroendocrinol 2015; 27:481-6. [PMID: 25612538 DOI: 10.1111/jne.12260] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 01/07/2015] [Accepted: 01/15/2015] [Indexed: 11/28/2022]
Abstract
Neural regulation of blood glucocorticoid levels is critical for defence of homeostasis during physiological or psychoemotional challenges. In mammals, this function is carried out by the neuroendocrine stress axis, coordinated by parvocellular neuroendocrine cells (PNCs) of the paraventricular hypothalamic nucleus. Feedback regulation of PNCs by glucocorticoids provides complex experience-dependent shaping of neuroendocrine responses. We review recent evidence for metaplastic actions of glucocorticoids as 'circuit breakers' at synapses directly regulating PNC excitability and explore how such mechanisms may serve as substrates for stress adaptation.
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Affiliation(s)
- J I Wamsteeker Cusulin
- Hotchkiss Brain Institute and the Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - J S Bains
- Hotchkiss Brain Institute and the Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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Feetham CH, Nunn N, Barrett-Jolley R. The depressor response to intracerebroventricular hypotonic saline is sensitive to TRPV4 antagonist RN1734. Front Pharmacol 2015; 6:83. [PMID: 25954200 PMCID: PMC4407506 DOI: 10.3389/fphar.2015.00083] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Accepted: 04/02/2015] [Indexed: 11/18/2022] Open
Abstract
Several reports have shown that the periventricular region of the brain, including the paraventricular nucleus (PVN), is critical to sensing and responding to changes in plasma osmolality. Further studies also implicate the transient receptor potential ion channel, type V4 (TRPV4) channel in this homeostatic behavior. In previous work we have shown that TRPV4 ion channels couple to calcium-activated potassium channels in the PVN to decrease action potential firing frequency in response to hypotonicity. In the present study we investigated whether, similarly, intracerebroventricular (ICV) application of hypotonic solutions modulated cardiovascular parameters, and if so whether this was sensitive to a TRPV4 channel inhibitor. We found that ICV injection of 270 mOsmol artificial cerebrospinal fluid (ACSF) decreased mean blood pressure, but not heart rate, compared to naïve mice or mice injected with 300 mOsmol ACSF. This effect was abolished by treatment with the TRPV4 inhibitor RN1734. These data suggest that periventricular targets within the brain are capable of generating depressor action in response to TRPV4 ion channel activation. Potentially, in the future, the TRPV4 channel, or the TRPV4–KCa coupling mechanism, may serve as a therapeutic target for treatment of cardiovascular disease.
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Affiliation(s)
- Claire H Feetham
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool Liverpool, UK
| | - Nicolas Nunn
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool Liverpool, UK
| | - Richard Barrett-Jolley
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool Liverpool, UK
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8
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Feetham CH, Nunn N, Lewis R, Dart C, Barrett-Jolley R. TRPV4 and K(Ca) ion channels functionally couple as osmosensors in the paraventricular nucleus. Br J Pharmacol 2015; 172:1753-68. [PMID: 25421636 PMCID: PMC4376454 DOI: 10.1111/bph.13023] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 11/13/2014] [Accepted: 11/16/2014] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND AND PURPOSE Transient receptor potential vanilloid type 4 (TRPV4) and calcium-activated potassium channels (KCa ) mediate osmosensing in many tissues. Both TRPV4 and KCa channels are found in the paraventricular nucleus (PVN) of the hypothalamus, an area critical for sympathetic control of cardiovascular and renal function. Here, we have investigated whether TRPV4 channels functionally couple to KCa channels to mediate osmosensing in PVN parvocellular neurones and have characterized, pharmacologically, the subtype of KCa channel involved. EXPERIMENTAL APPROACH We investigated osmosensing roles for TRPV4 and KCa channels in parvocellular PVN neurones using cell-attached and whole-cell electrophysiology in mouse brain slices and rat isolated PVN neurons. Intracellular Ca(2+) was recorded using Fura-2AM. The system was modelled in the NEURON simulation environment. KEY RESULTS Hypotonic saline reduced action current frequency in hypothalamic slices; a response mimicked by TRPV4 channel agonists 4αPDD (1 μM) and GSK1016790A (100 nM), and blocked by inhibitors of either TRPV4 channels (RN1734 (5 μM) and HC067047 (300 nM) or the low-conductance calcium-activated potassium (SK) channel (UCL-1684 30 nM); iberiotoxin and TRAM-34 had no effect. Our model was compatible with coupling between TRPV4 and KCa channels, predicting the presence of positive and negative feedback loops. These predictions were verified using isolated PVN neurons. Both hypotonic challenge and 4αPDD increased intracellular Ca(2+) and UCL-1684 reduced the action of hypotonic challenge. CONCLUSIONS AND IMPLICATIONS There was functional coupling between TRPV4 and SK channels in parvocellular neurones. This mechanism contributes to osmosensing in the PVN and may provide a novel pharmacological target for the cardiovascular or renal systems.
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Affiliation(s)
- C H Feetham
- Institute of Ageing and Chronic Disease, Faculty of Health & Life Sciences, University of LiverpoolLiverpool, L69 3GA, UK
| | - N Nunn
- Faculty of Life Sciences, University of ManchesterManchester, M13 9PT, UK
| | - R Lewis
- Institute of Ageing and Chronic Disease, Faculty of Health & Life Sciences, University of LiverpoolLiverpool, L69 3GA, UK
| | - C Dart
- Institute of Ageing and Chronic Disease, Faculty of Health & Life Sciences, University of LiverpoolLiverpool, L69 3GA, UK
| | - R Barrett-Jolley
- Institute of Ageing and Chronic Disease, Faculty of Health & Life Sciences, University of LiverpoolLiverpool, L69 3GA, UK
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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.
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Dysfunctional astrocytic and synaptic regulation of hypothalamic glutamatergic transmission in a mouse model of early-life adversity: relevance to neurosteroids and programming of the stress response. J Neurosci 2014; 33:19534-54. [PMID: 24336719 DOI: 10.1523/jneurosci.1337-13.2013] [Citation(s) in RCA: 113] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Adverse early-life experiences, such as poor maternal care, program an abnormal stress response that may involve an altered balance between excitatory and inhibitory signals. Here, we explored how early-life stress (ELS) affects excitatory and inhibitory transmission in corticotrophin-releasing factor (CRF)-expressing dorsal-medial (mpd) neurons of the neonatal mouse hypothalamus. We report that ELS associates with enhanced excitatory glutamatergic transmission that is manifested as an increased frequency of synaptic events and increased extrasynaptic conductance, with the latter associated with dysfunctional astrocytic regulation of glutamate levels. The neurosteroid 5α-pregnan-3α-ol-20-one (5α3α-THPROG) is an endogenous, positive modulator of GABAA receptors (GABAARs) that is abundant during brain development and rises rapidly during acute stress, thereby enhancing inhibition to curtail stress-induced activation of the hypothalamic-pituitary-adrenocortical axis. In control mpd neurons, 5α3α-THPROG potently suppressed neuronal discharge, but this action was greatly compromised by prior ELS exposure. This neurosteroid insensitivity did not primarily result from perturbations of GABAergic inhibition, but rather arose functionally from the increased excitatory drive onto mpd neurons. Previous reports indicated that mice (dams) lacking the GABAAR δ subunit (δ(0/0)) exhibit altered maternal behavior. Intriguingly, δ(0/0) offspring showed some hallmarks of abnormal maternal care that were further exacerbated by ELS. Moreover, in common with ELS, mpd neurons of δ(0/0) pups exhibited increased synaptic and extrasynaptic glutamatergic transmission and consequently a blunted neurosteroid suppression of neuronal firing. This study reveals that increased synaptic and tonic glutamatergic transmission may be a common maladaptation to ELS, leading to enhanced excitation of CRF-releasing neurons, and identifies neurosteroids as putative early regulators of the stress neurocircuitry.
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Nunn N, Womack M, Dart C, Barrett-Jolley R. Function and pharmacology of spinally-projecting sympathetic pre-autonomic neurones in the paraventricular nucleus of the hypothalamus. Curr Neuropharmacol 2011; 9:262-77. [PMID: 22131936 PMCID: PMC3131718 DOI: 10.2174/157015911795596531] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 09/01/2010] [Accepted: 09/14/2010] [Indexed: 12/16/2022] Open
Abstract
The paraventricular nucleus (PVN) of the hypothalamus has been described as the "autonomic master controller". It co-ordinates critical physiological responses through control of the hypothalamic-pituitary-adrenal (HPA)-axis, and by modulation of the sympathetic and parasympathetic branches of the central nervous system. The PVN comprises several anatomical subdivisions, including the parvocellular/ mediocellular subdivision, which contains neurones projecting to the medulla and spinal cord. Consensus indicates that output from spinally-projecting sympathetic pre-autonomic neurones (SPANs) increases blood pressure and heart rate, and dysfunction of these neurones has been directly linked to elevated sympathetic activity during heart failure. The influence of spinally-projecting SPANs on cardiovascular function high-lights their potential as targets for future therapeutic drug development. Recent studies have demonstrated pharmacological control of these spinally-projecting SPANs with glutamate, GABA, nitric oxide, neuroactive steroids and a number of neuropeptides (including angiotensin, substance P, and corticotrophin-releasing factor). The underlying mechanism of control appears to be a state of tonic inhibition by GABA, which is then strengthened or relieved by the action of other modulators. The physiological function of spinally-projecting SPANs has been subject to some debate, and they may be involved in physiological stress responses, blood volume regulation, glucose regulation, thermoregulation and/or circadian rhythms. This review describes the pharmacology of PVN spinally-projecting SPANs and discusses their likely roles in cardiovascular control.
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Affiliation(s)
| | | | | | - Richard Barrett-Jolley
- Centre for Integrative Mammalian Biology, University of Liverpool, Brownlow Hill & Crown St. Liverpool, L69 7ZJ, UK
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12
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Crewther BT, Cook C, Cardinale M, Weatherby RP, Lowe T. Two Emerging Concepts for Elite Athletes. Sports Med 2011; 41:103-23. [DOI: 10.2165/11539170-000000000-00000] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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13
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Wamsteeker JI, Bains JS. A synaptocentric view of the neuroendocrine response to stress. Eur J Neurosci 2010; 32:2011-21. [DOI: 10.1111/j.1460-9568.2010.07513.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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14
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King AP, Liberzon I. Assessing the neuroendocrine stress response in the functional neuroimaging context. Neuroimage 2009; 47:1116-24. [PMID: 19481160 DOI: 10.1016/j.neuroimage.2009.05.055] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 05/19/2009] [Accepted: 05/21/2009] [Indexed: 02/03/2023] Open
Abstract
Neural regulation of stress responses, and the feedback of stress hormones to the brain, reflect complex brain-body interactions that may underlie the effects of psychological stress on health. Elucidating the brain circuitry involved in the cortical control of limbic-hypothalamic-pituitary-adrenal axis, and the cortical "targets" of cortisol that in turn modulates brain function, requires careful assessment of glucocorticoid hormones, in the context of the neuroimaging paradigms. Here we discuss approaches for assessment of endocrine function in the context of neuroimaging, including methods of blood and saliva specimen collection, and methods for drug/hormone administration. We also briefly discuss important temporal considerations, including appropriate timing of sample collections for hormones with different time-courses of activation (e.g. ACTH vs. cortisol), the pharmacokinetics of both endogenous hormones and administered agents, and circadian considerations. These are crucial to experimental designs of rhythmic hormonal systems and multiple feedback loops. We briefly address psychological/behavioral 'activation' paradigms used for inducing endogenous LHPA axis responses within or in proximity to scanner, as well as strategies for administration of exogenous hormones or secretagogues. Finally, we discuss some of the analytical issues in terms of hormone responses (e.g. response and area under curve, diurnal variability) and strategies for linking measured levels of peripheral humoral factor to brain activity (e.g. hormone responses as between-subject regressors of BOLD activations, hormone levels as within-subject regressors in analyses of covariance of brain activity over time, etc.).
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Affiliation(s)
- Anthony P King
- Department of Psychiatry, University of Michigan, Ann Arbor, MI, USA
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Womack MD, Morris R, Gent TC, Barrett-Jolley R. Substance P targets sympathetic control neurons in the paraventricular nucleus. Circ Res 2007; 100:1650-8. [PMID: 17495222 DOI: 10.1161/circresaha.107.153494] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The paraventricular nucleus (PVN) contains spinally-projecting neurons implicated in fine-tuning the cardiovascular system. In vivo activity of "presympathetic" parvocellular neurons is suppressed by tonic inhibition from GABA-ergic inputs, inhibition of which increases sympathetic pressor activity and heart rate. Targeting of this specific neuronal population could potentially limit elevations of heart rate and blood pressure associated with disease. Here we show, for the first time, that "presympathetic" PVN neurons are disinhibited by the neuropeptide substance P (SP) acting via tachykinin NK1 receptor inhibition of GABA(A) currents. Application of SP to the paraventricular nucleus of rats increases heart rate and blood pressure. In in vitro brain slice experiments, in the presence of GABA, 1 micromol/L SP increased action current frequency by a factor of 2.7+/-0.6 (n=5, P< or =0.05, ANOVA). Furthermore, 1 micromol/L SP inhibited GABA(A) currents by 70+/-8% (n=8, P< or =0.005 paired t test). These effects were abolished by NK1 antagonists, but not NK2 and NK3 antagonists. GABA(A) inhibition was not reproduced by NK2 or NK3 agonists. The inhibition of parvocellular GABA(A) currents by SP was also abolished by a protein kinase C (PKC) inhibitor peptide and mimicked by application of phorbol-12-myristate-13-acetate (PMA), implicating a PKC-dependent mechanism. Single-channel analysis indicates that SP acts through reduction of channel mean open-time (cmot): GABA(A) cmot being reduced by approximately 60% by SP (P< or =0.05 ANOVA, Bonferroni). These data suggest that tachykinins mediate their pressor activity by increasing the excitability of spinally-projecting neurons and identifies NK1 receptors as potential targets for therapeutic modulation of the cardiovascular system.
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Affiliation(s)
- Matthew D Womack
- Veterinary Sciences Faculty, Brownlow Hill, University of Liverpool, UK
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Womack MD, Barrett-Jolley R. Activation of paraventricular nucleus neurones by the dorsomedial hypothalamus via a tachykinin pathway in rats. Exp Physiol 2007; 92:671-6. [PMID: 17468202 DOI: 10.1113/expphysiol.2007.037457] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The dorsomedial hypothalamus (DMH) innervates the paraventricular nucleus (PVN) with substance P (SP) immunoreactive neurones. The PVN itself powerfully influences both the neuroendocrine and the cardiovascular systems. In this in vitro study, we examine the DMH-to-PVN pathway electrophysiologically. Glutamate application to the DMH increased action current frequency in the PVN. This effect was prevented by the glutamate antagonist kynurenic acid or by synaptic block with a high-Mg(2)(+) low-Ca(2)(+) buffer solution. Crucially, the selective tachykinin NK1 receptor antagonist L-703606 also inhibited DMH-to-PVN neurotransmission. Thus we show, for the first time, an excitatory connection between the DMH and PVN that uses tachykinin NK1 receptors. This pathway may be important for the hypothalamic control of neuroendocrine and/or cardiovascular function.
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Affiliation(s)
- Matthew D Womack
- Department of Veterinary Preclinical Sciences, Veterinary Sciences Building, Brownlow Hill & Crown Street, University of Liverpool, Liverpool L69 7ZJ, UK
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Abstract
Glucocorticoids are secreted into the systemic circulation from the adrenal cortex and initiate a broad range of actions throughout the organism that regulate the function of multiple organ systems, including the liver, muscle, the immune system, the pancreas, fat tissue, and the brain. Delayed glucocorticoid effects are mediated by classical steroid mechanisms involving transcriptional regulation. Relatively rapid effects of glucocorticoids also occur that are incompatible with genomic regulation and invoke a noncanonical mode of steroid action. Studies conducted in several labs and on different species suggest that the rapid effects of glucocorticoids are mediated by the activation of one or more membrane-associated receptors. Here, we provide a brief review focused on multiple lines of evidence suggesting that rapid glucocorticoid actions are triggered by, or at least dependent on, membrane-associated G protein-coupled receptors and activation of downstream signaling cascades. We also discuss the possibility that membrane-initiated actions of glucocorticoids may provide an additional mechanism for the regulation of gene transcription.
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Affiliation(s)
- Jeffrey G Tasker
- Department of Cell and Molecular Biology, Tulane University, 6400 Freret Street, New Orleans, Louisiana 70118, USA.
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Womack MD, Pyner S, Barrett-Jolley R. Inhibition by alpha-tetrahydrodeoxycorticosterone (THDOC) of pre-sympathetic parvocellular neurones in the paraventricular nucleus of rat hypothalamus. Br J Pharmacol 2006; 149:600-7. [PMID: 17001301 PMCID: PMC2014678 DOI: 10.1038/sj.bjp.0706911] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE alpha-tetrahydrodeoxycorticosterone (THDOC) is an endogenous neuroactive steroid which increases in plasma and brain concentration during stress. It has both positive and negative modulatory effects on GABA activated GABAA currents, dependent upon the dose. We investigated the effects of THDOC on spinally-projecting "pre-sympathetic" neurones in the parvocellular subnucleus of the hypothalamic paraventricular nucleus (PVN), to determine whether it activates or inhibits these neurones, and by what mechanism. EXPERIMENTAL APPROACH Rat spinally-projecting (parvocellular) PVN neurones were identified by retrograde labelling and the action of THDOC investigated with three modes of patch-clamp: cell-attached action current, whole-cell voltage-clamp and cell-attached single-channel recording. KEY RESULTS In cell-attached patch mode, parvocellular neurones fired action potentials spontaneously with an average frequency of 3.6 +/- 1.1 Hz. Bath application of THDOC reduced this with an EC50 of 67 nM (95% confidence limits: 54 to 84 nM), Hill coefficient 0.8 +/- 0.04, n = 5. In whole-cell patch-clamp mode, pressure ejection of GABA evoked inward currents. These were clearly GABAA currents, since they were inhibited by the GABAA receptor antagonist bicuculline, and reversed near the chloride equilibrium potential. THDOC significantly potentiated GABAA currents (1 microM THDOC: 148 +/- 15% of control, n = 5, p < or = 0.05, ANOVA). Single-channel analysis showed no differences in conductance or corrected mean open times in the presence of 1 microM THDOC. CONCLUSIONS AND IMPLICATIONS THDOC inhibited parvocellular neuronal activity without showing any evidence of the bidirectional activity demonstrated previously with cultured hypothalamic neurones. Our data are consistent with the hypothesis that THDOC acts by potentiating the post-synaptic activity of endogenously released GABA.
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Affiliation(s)
- M D Womack
- Department of Veterinary Preclinical Sciences, University of Liverpool Liverpool, UK
| | - S Pyner
- School of Biological & Biomedical Sciences, Science Laboratories, University of Durham Durham, UK
| | - R Barrett-Jolley
- Department of Veterinary Preclinical Sciences, University of Liverpool Liverpool, UK
- Author for correspondence:
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Penland SN, Morrow AL. 3alpha,5beta-Reduced cortisol exhibits antagonist properties on cerebral cortical GABA(A) receptors. Eur J Pharmacol 2005; 506:129-32. [PMID: 15588732 DOI: 10.1016/j.ejphar.2004.11.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2004] [Accepted: 11/02/2004] [Indexed: 11/25/2022]
Abstract
The tetrahydro-reduced derivatives of progesterone and deoxycorticosterone, allopregnanolone, and tetrahydrodeoxycorticosterone are potent positive modulators of GABA(A) receptors that are elevated by hypothalamic-pituitary-adrenal axis activation in rodents. In humans, 11-deoxycortisol and cortisol are important hypothalamic-pituitary-adrenal axis steroids. We hypothesized that C(3,5) reduction of 11-deoxycortisol and cortisol generates steroids with GABA(A) receptor activity. 3alpha,5beta-Reduced cortisol dose-dependently inhibited muscimol-stimulated chloride flux and tetrahydrodeoxycorticosterone potentiation of muscimol responses. Cortisol, 11-deoxycortisol, 5alpha-dihydrocortisol, 3alpha,5alpha-reduced cortisol, 3alpha,5alpha-reduced 11-deoxycortisol, and 3alpha,5beta-reduced 11-deoxycortisol had no activity at 1 muM and weaker negative modulatory activity at 10 muM. We conclude that cortisol metabolism may produce antagonistic GABAergic activity.
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Affiliation(s)
- Shannon N Penland
- Department of Pharmacology, Bowles Center for Alcohol Studies, CB No. 7178, 3027 Thurston Bowles Building, UNC School of Medicine, Chapel Hill, NC 27599, USA
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Verkuyl JM, Karst H, Joëls M. GABAergic transmission in the rat paraventricular nucleus of the hypothalamus is suppressed by corticosterone and stress. Eur J Neurosci 2005; 21:113-21. [PMID: 15654848 DOI: 10.1111/j.1460-9568.2004.03846.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Parvocellular neurons in the hypothalamic paraventricular nucleus receive hormonal inputs mediated by corticosterone as well as neuronal inputs, prominent among which is a GABAergic inhibitory projection. In the present study we examined the functional properties of this GABAergic innervation when corticosteroid levels fluctuate. Frequency, amplitude and kinetic properties of miniature inhibitory postsynaptic potentials (mIPSCs), mediated by gamma amino butyric acid (GABA) were studied with whole cell recording in parvocellular neurons. Injection of a high dose of corticosterone in vivo suppressed the frequency but did not change the amplitude and kinetic properties of mIPSCs recorded 1-5 h later in vitro. Similar effects were observed after restraint stress. The corticosteroid actions do not require involvement of extrahypothalamic brain regions, because in vitro administration of 100 nM corticosterone (20 min) directly to a hypothalamic slice also suppressed the frequency of mIPSCs recorded several hours later. Corticosterone administration to hypothalamic slices from restraint rats did not result in stronger reduction of mIPSC frequency than either treatment alone, pointing to a common underlying mechanism. Paired pulse response inhibition was reduced by corticosterone, suggesting that the hormone decreases the release probability of GABA-containing vesicles. Unlike neurosteroids, corticosterone induced no rapid effects on mIPSC properties. These results indicate that increases in glucocorticoid level due to stress can slowly but persistently inhibit the GABAergic tone on parvocellular hypothalamic neurons via a hitherto unknown local mechanism independent of limbic projections.
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Affiliation(s)
- J Martin Verkuyl
- Swammerdam Institute for Life Sciences, section Neurobiology, University of Amsterdam, Kruislaan 320, 1098 SM Amsterdam, The Netherlands
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Kristensen MP, Rector DM, Poe GR, Harper RM. Activity changes of the cat paraventricular hypothalamus during stressor exposure. Neuroreport 2004; 15:43-8. [PMID: 15106829 DOI: 10.1097/00001756-200401190-00010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Dorso-medial paraventricular hypothalamus (PVH) activity was assessed by light scattering procedures in freely behaving cats during auditory stressor exposure. Acoustic noise (> 95dB) raised plasma ACTH concentrations, somatic muscle tonus, respiratory frequency and cardiac rates; PVH activity peaked 0.8s following stimulation, and then markedly declined below baseline to a trough at 9.7s. Hypothalamic responses were not uniformly distributed across the recorded PVH field. Activity changes emerged from subregions within the visualized area, and were widespread at the overall activity zenith and nadir. Isolated pixels appeared opposite in activity pattern to overall changes. We suggest that transient activity increases represent initial PVH neural stress responses, and that subsequent profound declines result from neural inhibitory feedback.
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Affiliation(s)
- Morten P Kristensen
- The Brain Research Institute, David Geffen School of Medicine at UCLA, University of California at Los Angeles, 10833 Le Conte Avenue, Los Angeles, CA 90095-1763, USA
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