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Ichiyama A, Mestern S, Benigno GB, Scott KE, Allman BL, Muller L, Inoue W. State-dependent activity dynamics of hypothalamic stress effector neurons. eLife 2022; 11:76832. [PMID: 35770968 PMCID: PMC9278954 DOI: 10.7554/elife.76832] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 06/17/2022] [Indexed: 11/30/2022] Open
Abstract
The stress response necessitates an immediate boost in vital physiological functions from their homeostatic operation to an elevated emergency response. However, the neural mechanisms underlying this state-dependent change remain largely unknown. Using a combination of in vivo and ex vivo electrophysiology with computational modeling, we report that corticotropin releasing hormone (CRH) neurons in the paraventricular nucleus of the hypothalamus (PVN), the effector neurons of hormonal stress response, rapidly transition between distinct activity states through recurrent inhibition. Specifically, in vivo optrode recording shows that under non-stress conditions, CRHPVN neurons often fire with rhythmic brief bursts (RB), which, somewhat counterintuitively, constrains firing rate due to long (~2 s) interburst intervals. Stressful stimuli rapidly switch RB to continuous single spiking (SS), permitting a large increase in firing rate. A spiking network model shows that recurrent inhibition can control this activity-state switch, and more broadly the gain of spiking responses to excitatory inputs. In biological CRHPVN neurons ex vivo, the injection of whole-cell currents derived from our computational model recreates the in vivo-like switch between RB and SS, providing direct evidence that physiologically relevant network inputs enable state-dependent computation in single neurons. Together, we present a novel mechanism for state-dependent activity dynamics in CRHPVN neurons.
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Jaszczyk A, Juszczak GR. Glucocorticoids, metabolism and brain activity. Neurosci Biobehav Rev 2021; 126:113-145. [PMID: 33727030 DOI: 10.1016/j.neubiorev.2021.03.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 03/04/2021] [Accepted: 03/07/2021] [Indexed: 12/17/2022]
Abstract
The review integrates different experimental approaches including biochemistry, c-Fos expression, microdialysis (glutamate, GABA, noradrenaline and serotonin), electrophysiology and fMRI to better understand the effect of elevated level of glucocorticoids on the brain activity and metabolism. The available data indicate that glucocorticoids alter the dynamics of neuronal activity leading to context-specific changes including both excitation and inhibition and these effects are expected to support the task-related responses. Glucocorticoids also lead to diversification of available sources of energy due to elevated levels of glucose, lactate, pyruvate, mannose and hydroxybutyrate (ketone bodies), which can be used to fuel brain, and facilitate storage and utilization of brain carbohydrate reserves formed by glycogen. However, the mismatch between carbohydrate supply and utilization that is most likely to occur in situations not requiring energy-consuming activities lead to metabolic stress due to elevated brain levels of glucose. Excessive doses of glucocorticoids also impair the production of energy (ATP) and mitochondrial oxidation. Therefore, glucocorticoids have both adaptive and maladaptive effects consistently with the concept of allostatic load and overload.
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Affiliation(s)
- Aneta Jaszczyk
- Department of Animal Behavior and Welfare, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, 05-552 Jastrzebiec, 36a Postepu str., Poland
| | - Grzegorz R Juszczak
- Department of Animal Behavior and Welfare, Institute of Genetics and Animal Biotechnology, Polish Academy of Sciences, 05-552 Jastrzebiec, 36a Postepu str., Poland.
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Abstract
The hypothalamo-pituitary-adrenal axis (HPA) is responsible for stimulation of adrenal corticosteroids in response to stress. Negative feedback control by corticosteroids limits pituitary secretion of corticotropin, ACTH, and hypothalamic secretion of corticotropin-releasing hormone, CRH, and vasopressin, AVP, resulting in regulation of both basal and stress-induced ACTH secretion. The negative feedback effect of corticosteroids occurs by action of corticosteroids at mineralocorticoid receptors (MR) and/or glucocorticoid receptors (GRs) located in multiple sites in the brain and in the pituitary. The mechanisms of negative feedback vary according to the receptor type and location within the brain-hypothalmo-pituitary axis. A very rapid nongenomic action has been demonstrated for GR action on CRH neurons in the hypothalamus, and somewhat slower nongenomic effects are observed in the pituitary or other brain sites mediated by GR and/or MR. Corticosteroids also have genomic actions, including repression of the pro-opiomelanocortin (POMC) gene in the pituitary and CRH and AVP genes in the hypothalamus. The rapid effect inhibits stimulated secretion, but requires a rapidly rising corticosteroid concentration. The more delayed inhibitory effect on stimulated secretion is dependent on the intensity of the stimulus and the magnitude of the corticosteroid feedback signal, but also the neuroanatomical pathways responsible for activating the HPA. The pathways for activation of some stressors may partially bypass hypothalamic feedback sites at the CRH neuron, whereas others may not involve forebrain sites; therefore, some physiological stressors may override or bypass negative feedback, and other psychological stressors may facilitate responses to subsequent stress.
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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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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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King AP, Abelson JL, Britton JC, Phan KL, Taylor SF, Liberzon I. Medial prefrontal cortex and right insula activity predict plasma ACTH response to trauma recall. Neuroimage 2009; 47:872-80. [DOI: 10.1016/j.neuroimage.2009.05.088] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 05/22/2009] [Accepted: 05/26/2009] [Indexed: 10/20/2022] Open
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Zoccal DB, Bonagamba LGH, Antunes-Rodrigues J, Machado BH. Plasma corticosterone levels is elevated in rats submitted to chronic intermittent hypoxia. Auton Neurosci 2007; 134:115-7. [PMID: 17293169 DOI: 10.1016/j.autneu.2007.01.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Revised: 01/08/2007] [Accepted: 01/09/2007] [Indexed: 11/15/2022]
Abstract
In the present study we investigated whether plasma corticosterone is altered in rats exposed to chronic intermittent hypoxia (CIH). Rats were submitted to a fraction of inspired oxygen of 6%, for 40 s, every 9 min, 8 h a day, for 35 days (CIH rats, n=17), while control rats were maintained under normoxic conditions (n=16). After CIH, the rats presented a significant increase in baseline mean arterial pressure (118+/-2 vs 106+/-3, mmHg) but not in baseline heart rate (381+/-17 vs 362+/-12 bpm) when compared to the control rats. Besides, a significant increase in plasma corticosterone was observed in CIH rats in comparison to the control rats (39+/-4 vs 20+/-2 microg/dl). Considering that corticosterone can affect both peripheral and central sympathetic mechanisms, the elevated plasma corticosterone may represent a new insight on the mechanisms underlying the hypertension observed after CIH.
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Affiliation(s)
- Daniel B Zoccal
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil
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Herman JP, Cullinan WE, Ziegler DR, Tasker JG. Role of the paraventricular nucleus microenvironment in stress integration. Eur J Neurosci 2002; 16:381-5. [PMID: 12193178 DOI: 10.1046/j.1460-9568.2002.02133.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The hypothalamic paraventricular nucleus is the primary controller of hypothalamo-pituitary-adrenocortical glucocorticoid release. In performing this function, the paraventricular nucleus summates a variety of information from both external and internal sources into a net secretory signal to the adrenal cortex. In this review, we will provide an overview of neuronal circuit mechanisms governing activation and inhibition of hypophysiotrophic neurons, highlight recent developments in our understanding of nonsynaptic mechanisms regulating paraventricular cellular activity, including dendritic neuropeptide release, direct steroid feedback, cytokine cascades and gaseous neurotransmission, and illustrate the capacity for hypophysiotrophic, neurohypophysial and preautonomic paraventricular effector pathways to work together in control of glucocorticoid release. The current state of knowledge reveals the paraventricular nucleus to be a dynamic entity, capable of integrating diverse classes of signals into control of adrenocortical activation.
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Affiliation(s)
- James P Herman
- Department of Psychiatry, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH 45267, USA.
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Scheuer DA, Mifflin SW. Glucocorticoids modulate baroreflex control of renal sympathetic nerve activity. Am J Physiol Regul Integr Comp Physiol 2001; 280:R1440-9. [PMID: 11294766 DOI: 10.1152/ajpregu.2001.280.5.r1440] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Experiments were performed to determine the effects of glucocorticoids on arterial baroreceptor reflex control of renal sympathetic nerve activity (RSNA). Intravenous infusions of phenylephrine and nitroprusside were used to produce graded changes in arterial pressure (AP) in Inactin-anesthetized male Sprague-Dawley rats. Baroreflex control of RSNA was determined during a baseline period and 2 and 3 h after administration of the glucocorticoid type II receptor antagonist Mifepristone (30 mg/kg sc) or vehicle (oil). Corticosterone (cort) treatment (100 mg cort pellet sc for 2-3 wk) increased baseline AP from 115 +/- 2 to 128 +/- 1 mmHg. Cort treatment also decreased the gain coefficient and increased the midpoint of the baroreflex curve. Treatment of cort rats with Mifepristone decreased AP within 2 h and increased the gain coefficient and decreased the midpoint of the baroreflex function curve back toward values measured in control rats. Mifepristone altered the baroreflex function curve even when AP was maintained at baseline levels. Therefore, these data demonstrate for the first time that glucocorticoids can modulate baroreflex control of RSNA by a mechanism that is, in part, independent of changes in AP.
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Affiliation(s)
- D A Scheuer
- Department of Pharmacology, The University of Missouri, Kansas City, Missouri 64108, USA.
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Champagne D, Beaulieu J, Drolet G. CRFergic innervation of the paraventricular nucleus of the rat hypothalamus: a tract-tracing study. J Neuroendocrinol 1998; 10:119-31. [PMID: 9535058 DOI: 10.1046/j.1365-2826.1998.00179.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
It has been reported that corticotropin-releasing factor (CRF) may regulate its own biosynthesis in the paraventricular nucleus of the hypothalamus (PVH). Whether this CRF autoregulation is mediated by local circuitry or from extra-PVH CRF neuronal fibers terminating on CRF perikarya within the PVH is unknown. In the present study, we sought to determine the origin(s) of this CRF innervation using retrograde transport of wheat germ-conjugated-gold particles (WGA-apoHRP-Au) combined with immunohistochemistry for CRF. The rats also received colchicine (100 microg, icv) 5-7 days after tracer injection and were perfused 24 h later. Results of retrograde labeling with pressure injections of WGA-apoHRP-Au centered to PVH and subsequent immunohistochemical staining for CRF demonstrated numerous retrogradely labeled CRF neurons in the perifornical hypothalamic nucleus (PeF), the dorsolateral hypothalamic area (DA) (medial and lateral portions) and the dorsomedial nucleus of the hypothalamus (DMH). Smaller groups of CRF-ir neurons that were retrogradely labeled were found in the bed nuclei of the stria terminalis (BnST), the Barrington's nucleus (Bar) and the dorsal raphé (DR). These CRFergic pathways to the PVH may represent an anatomical substrate underlying the function of the stress-integrative PVH neurons in the autonomic, behavioral and neuroendocrine regulation during the stress response, including CRF autoregulation.
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Affiliation(s)
- D Champagne
- Centre Hospitalier Universitaire de Québec, Unité de Recherche en Neuroscience, Canada
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Feldman S, Weidenfeld J. Hypothalamic mechanisms mediating glutamate effects on the hypothalamo-pituitary-adrenocortical axis. J Neural Transm (Vienna) 1998; 104:633-42. [PMID: 9444563 DOI: 10.1007/bf01291881] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The effect of local administration of glutamate into the hypothalamic paraventricular nucleus (PVN) on the hypothalamo-pituitary adrenocortical (HPA) axis was studied in male rats. Glutamate caused CRH-41 depletion from the median eminence (ME) and a consequent rise in ACTH and corticosterone (CS) serum levels. In rats pretreated with systemic dexamethasone (dex) these effects were completely inhibited. The administration of the glucocorticoid receptor antagonist RU-38486 abolished the inhibitory effect of dex on the adrenocortical discharge. In addition, the depletion of hypothalamic norepinephrine (NE) and serotonin (5-HT) by specific neurotoxins administered into the ventral noradrenergic blundle or into the raphe nuclei respectively, inhibited the response of serum ACTH and CS following PVN glutamate administration. These data indicate that glutamate stimulated the HPA axis via the release of ME CRH-41 into the portal circulation. This response is steroid sensitive involving type II glucocorticoid receptors. Hypothalamic NE and 5-HT participate in the glutamate induced HPA axis activation.
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Affiliation(s)
- S Feldman
- Department of Neurology, Hadassah University Hospital, Jerusalem, Israel
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Chapter 8 Neuroendocrine Aspects of the Aging Brain. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1566-3124(08)60058-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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13
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Feldman S, Weidenfeld J. Neural mechanisms involved in the corticosteroid feedback effects on the hypothalamo-pituitary-adrenocortical axis. Prog Neurobiol 1995; 45:129-41. [PMID: 7724796 DOI: 10.1016/0301-0082(94)00039-k] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- S Feldman
- Department of Neurology, Hadassah University Hospital, Jerusalem, Israel
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Feldman S, Weidenfeld J. The dorsal hippocampus modifies the negative feedback effect of glucocorticoids on the adrenocortical and median eminence CRF-41 responses to photic stimulation. Brain Res 1993; 614:227-32. [PMID: 8348315 DOI: 10.1016/0006-8993(93)91039-u] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In the present study we have evaluated the role of the dorsal hippocampus on the negative feedback effect of glucocorticoids (GC) following photic stimulation. In hippocampectomized rats the recovery of serum corticosterone (CS) to basal levels following photic stimulation, was significantly attenuated in relation to sham hippocampectomized rats. The inhibitory effect of either systemic dexamethasone administration or CS implanted in the paraventricular nucleus (PVN), on the adrenocortical responses to photic stimulation, was completely prevented in hippocampectomized rats in comparison to sham operated animals. In rats with sham operation, the depletion of median eminence CRF-41 induced by photic stimulation, was prevented by pretreatment with CS PVN implants or systemic dexamethasone. These effects were reversed in rats with dorsal hippocampectomy. The results suggest that the dorsal hippocampus modulates the negative feedback of GC on the adrenocortical response following photic stimulation at the PVN level and this effect is mediated by median eminence CRF-41.
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Affiliation(s)
- S Feldman
- Department of Neurology, Hadassah University Hospital, Jerusalem, Israel
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Whitnall MH. Regulation of the hypothalamic corticotropin-releasing hormone neurosecretory system. Prog Neurobiol 1993; 40:573-629. [PMID: 8484004 DOI: 10.1016/0301-0082(93)90035-q] [Citation(s) in RCA: 452] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- M H Whitnall
- Department of Physiology, Armed Forces Radiobiology Research Institute, Bethesda, MD 20889-5145
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