scholarly journals Acute Stress Increases the Synthesis of 7α-Hydroxypregnenolone, a New Key Neurosteroid Stimulating Locomotor Activity, through Corticosterone Action in Newts

Endocrinology ◽  
2012 ◽  
Vol 153 (2) ◽  
pp. 794-805 ◽  
Author(s):  
Shogo Haraguchi ◽  
Teppei Koyama ◽  
Itaru Hasunuma ◽  
Shin-ichiro Okuyama ◽  
Takayoshi Ubuka ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Restraint Stress ◽  
Acute Stress ◽  
Behavioral Responses ◽  
Biological Action ◽  
Central Administration ◽  
Steroidogenic Enzyme ◽  
Dorsomedial Hypothalamus ◽  
The Brain ◽  
Double Immunolabeling

7α-Hydroxypregnenolone (7α-OH PREG) is a newly identified bioactive neurosteroid stimulating locomotor activity in the brain of newt, a wild animal, which serves as an excellent model to investigate the biosynthesis and biological action of neurosteroids. Here, we show that acute stress increases 7α-OH PREG synthesis in the dorsomedial hypothalamus (DMH) through corticosterone (CORT) action in newts. A 30-min restraint stress increased 7α-OH PREG synthesis in the brain tissue concomitant with the increase in plasma CORT concentrations. A 30-min restraint stress also increased the expression of cytochrome P4507α (CYP7B), the steroidogenic enzyme of 7α-OH PREG formation, in the DMH. Decreasing plasma CORT concentrations by hypophysectomy or trilostane administration decreased 7α-OH PREG synthesis in the diencephalon, whereas administration of CORT to these animals increased 7α-OH PREG synthesis. Glucocorticoid receptor was present in DMH neurons expressing CYP7B. Thus, CORT appears to act directly on DMH neurons to increase 7α-OH PREG synthesis. We further investigated the biological action of 7α-OH PREG in the brain under stress. A 30-min restraint stress or central administration of 7α-OH PREG increased serotonin concentrations in the diencephalon. Double immunolabeling further showed colocalization of CYP7B and serotonin in the DMH. These results indicate that acute stress increases the synthesis of 7α-OH PREG via CORT action in the DMH, and 7α-OH PREG activates serotonergic neurons in the DMH that may coordinate behavioral responses to stress. This is the first demonstration of neurosteroid biosynthesis regulated by peripheral steroid hormone and of neurosteroid action in the brain under stress in any vertebrate class.

Central administration of rat IL-6 induces HPA activation and fever but not sickness behavior in rats

1999 ◽  
Vol 276 (3) ◽  
pp. R652-R658 ◽  
Author(s):  
M. J. P. Lenczowski ◽  
R.-M. Bluthé ◽  
J. Roth ◽  
G. S. Rees ◽  
D. A. Rushforth ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Behavioral Responses ◽  
Sickness Behavior ◽  
Locomotor Behavior ◽  
Behavioral Changes ◽  
Intracerebroventricular Administration ◽  
Central Administration ◽  
Investigatory Behavior ◽  
Sites Of Action ◽  
The Brain

Interleukin (IL)-6 has been proposed to mediate several sickness responses, including brain-mediated neuroendocrine, temperature, and behavioral changes. However, the exact mechanisms and sites of action of IL-6 are still poorly understood. In the present study, we describe the effects of central administration of species-homologous recombinant rat IL-6 (rrIL-6) on the induction of hypothalamic-pituitary-adrenal (HPA) activity, fever, social investigatory behavior, and immobility. After intracerebroventricular administration of rrIL-6 (50 or 100 ng/rat), rats demonstrated HPA and febrile responses. In contrast, rrIL-6 alone did not induce changes in social investigatory and locomotor behavior at doses of up to 400 ng/rat. Coadministration of rrIL-6 (100 ng/rat) and rrIL-1β (40 ng/rat), which alone did not affect the behavioral responses, reduced social investigatory behavior and increased the duration of immobility. Compared with rhIL-6, intracerebroventricular administration of rrIL-6 (100 ng/rat) induced higher HPA responses and early-phase febrile responses. This is consistent with a higher potency of rrIL-6, compared with rhIL-6, in the murine B9 bioassay. We conclude that species-homologous rrIL-6 alone can act in the brain to induce HPA and febrile responses, whereas it only reduces social investigatory behavior and locomotor activity in the presence of IL-1β.

scholarly journals Maintenance of Gonadotropin Secretion by Glucocorticoids under Stress Conditions through the Inhibition of Prostaglandin Synthesis in the Brain

Endocrinology ◽  
2006 ◽  
Vol 147 (3) ◽  
pp. 1087-1093 ◽  
Author(s):  
Takashi Matsuwaki ◽  
Yuko Kayasuga ◽  
Keitaro Yamanouchi ◽  
Masugi Nishihara
Keyword(s):  
Restraint Stress ◽  
Acute Stress ◽  
Reproductive Function ◽  
Stress Conditions ◽  
Ovariectomized Rats ◽  
Gonadotropin Secretion ◽  
Inhibition Of Prostaglandin Synthesis ◽  
Corticosterone Treatment ◽  
Factor Α ◽  
The Brain

We have previously reported that glucocorticoids counteract the suppressive effects of tumor necrosis factor-α on both pulsatile and surge secretion of LH. This suggests that glucocorticoids have a protective effect on reproductive function under infectious stress. In the present study, we examined whether glucocorticoids maintain pulsatile LH secretion under various conditions of acute stress and the possible involvement of prostaglandins (PGs) in glucocorticoid actions. Three different types of stressors, namely infectious (lipopolysaccharide, 0.5 μg/kg), hypoglycemic (2-deoxy-d-glucose, 100 mg/kg), and restraint stress (1 h) were applied to ovariectomized rats. In ovariectomized rats, LH pulses were partially suppressed by restraint, but not by lipopolysaccharide or 2-deoxy-d-glucose. On the other hand, adrenalectomy (ADX) significantly enhanced the suppressive effects of all the stressors applied on LH pulses. Treatment with both corticosterone (25 mg/kg) and indomethacin (10 mg/kg) in ADX rats significantly attenuated the suppressive effects of these stressors on LH pulses. In addition, the immunoreactivity of cyclooxygenase-2, a PG-synthesizing enzyme, in the brain under stress conditions was much enhanced by ADX, and this was counteracted by corticosterone treatment. Similarly, an increase in body temperature under restraint stress was enhanced by ADX and suppressed by corticosterone. These results suggest that suppression of LH pulsatility by stress is mediated by PGs in the brain, and that increased release of endogenous glucocorticoids in response to stress counteracts this suppression by inhibiting PG synthesis, and thereby maintains reproductive function regardless of the nature of the stressor.

scholarly journals Prolactin Increases the Synthesis of 7α-Hydroxypregnenolone, a Key Factor for Induction of Locomotor Activity, in Breeding Male Newts

Endocrinology ◽  
2010 ◽  
Vol 151 (5) ◽  
pp. 2211-2222 ◽  
Author(s):  
Shogo Haraguchi ◽  
Teppei Koyama ◽  
Itaru Hasunuma ◽  
Hubert Vaudry ◽  
Kazuyoshi Tsutsui
Keyword(s):  
Locomotor Activity ◽  
Seasonal Changes ◽  
Maximum Level ◽  
Breeding Period ◽  
Preoptic Nucleus ◽  
Steroidogenic Enzyme ◽  
Key Factor ◽  
Dose Dependent Increase ◽  
Dose Dependent ◽  
The Brain

We recently found that the Japanese red-bellied newt, Cynops pyrrhogaster, actively produces 7α-hydroxypregnenolone, a previously undescribed amphibian neurosteroid. 7α-Hydroxypregnenolone stimulates locomotor activity of male newts. Locomotor activity of male newts increases during the breeding period as in other wild animals, but the molecular mechanism for such a change in locomotor activity is poorly understood. Here we show that the adenohypophyseal hormone prolactin (PRL) stimulates 7α-hydroxypregnenolone synthesis in the brain, thus increasing locomotor activity of breeding male newts. In this study, cytochrome P4507α (CYP7B), a steroidogenic enzyme catalyzing the formation of 7α-hydroxypregnenolone, was first identified to analyze seasonal changes in 7α-hydroxypregnenolone synthesis. Only males exhibited marked seasonal changes in 7α-hydroxypregnenolone synthesis and CYP7B expression in the brain, with a maximum level in the spring breeding period when locomotor activity of males increases. Subsequently we identified PRL as a key component of the mechanism regulating 7α-hydroxypregnenolone synthesis. Hypophysectomy decreased 7α-hydroxypregnenolone synthesis in the male brain, whereas administration of PRL but not gonadotropins to hypophysectomized males caused a dose-dependent increase in 7α-hydroxypregnenolone synthesis. To analyze the mode of PRL action, CYP7B and the receptor for PRL were localized in the male brain. PRL receptor was expressed in the neurons expressing CYP7B in the magnocellular preoptic nucleus. Thus, PRL appears to act directly on neurosteroidogenic magnocellular preoptic nucleus neurons to regulate 7α-hydroxypregnenolone synthesis, thus inducing seasonal locomotor changes in male newts. This is the first report describing the regulation of neurosteroidogenesis in the brain by an adenohypophyseal hormone in any vertebrate.

scholarly journals Putative Activation of the CB1 Cannabinoid Receptors Prevents Anxiety-Like Behavior, Oxidative Stress, and GABA Decrease in the Brain of Zebrafish Submitted to Acute Restraint Stress

2021 ◽  
Vol 14 ◽  
Author(s):  
Waldo Lucas Luz ◽  
Mateus Santos-Silva ◽  
Patrick Bruno Cardoso ◽  
Nadyme Assad ◽  
Edinaldo Rogério da Silva Moraes ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Restraint Stress ◽  
Cannabinoid Receptors ◽  
Acute Stress ◽  
Control Treatment ◽  
Cb1 Receptors ◽  
Acute Restraint Stress ◽  
Gaba Content ◽  
The Brain

Anxiety disorder is a well-recognized condition observed in subjects submitted to acute stress. Although the brain mechanisms underlying this disorder remain unclear, the available evidence indicates that oxidative stress and GABAergic dysfunction mediate the generation of stress-induced anxiety. Cannabinoids are known to be efficient modulators of behavior, given that the activation of the cannabinoid receptors type-1 (CB1 receptors) induces anxiolytic-like effects in animal models. In the present study, we aimed to describe the effects of the stimulation of the CB1 receptors on anxiety-like behavior, oxidative stress, and the GABA content of the brains of zebrafish submitted to acute restraint stress (ARS). The animals submitted to the ARS protocol presented evident anxiety-like behavior with increased lipid peroxidation in the brain tissue. The evaluation of the levels of GABA in the zebrafish telencephalon presented decreased levels of GABA in the ARS group in comparison with the control. Treatment with ACEA, a specific CB1 receptor agonist, prevented ARS-induced anxiety-like behavior and oxidative stress in the zebrafish brain. ACEA treatment also prevented a decrease in GABA in the telencephalon of the animals submitted to the ARS protocol. Overall, these preclinical data strongly suggest that the CB1 receptors represent a potential target for the development of the treatment of anxiety disorders elicited by acute stress.

Stress and Neuroimmunology

2021 ◽  
Author(s):  
Eric S. Wohleb
Keyword(s):  
Stress Responses ◽  
Acute Stress ◽  
Stress Hormones ◽  
Behavioral Responses ◽  
Molecular Signaling ◽  
Cellular Mechanisms ◽  
Ongoing Research ◽  
Stress Effects ◽  
Peripheral Immune Cells ◽  
The Brain

Stress is experienced when stimuli pose a perceived or actual threat to an organism. Exposure to a stressor initiates physiological and behavioral responses that are aimed at restoring homeostasis. In particular, stress activates the hypothalamic-pituitary-adrenal axis, leading to release of glucocorticoids, and engages the autonomic nervous system, causing release of norepinephrine. These “stress hormones” have widespread effects, because most cells express respective receptors that initiate cell-type-specific molecular signaling pathways. In the brain, acute stress promotes neuronal activation, resulting in alertness and adaptive behavioral responses. However, chronic or uncontrolled stress exposure can have deleterious effects on neuronal function, including loss of synaptic connections, which leads to behavioral and cognitive impairments. Stress responses also influence the function of brain-resident microglia and peripheral immune cells that interact with the brain, and alterations in these neuroimmune systems can contribute to the neurobiological and behavioral effects of chronic stress. Ongoing research is aimed at uncovering the molecular and cellular mechanisms that mediate stress effects on neuroimmune systems, and vice versa.

The dorsomedial hypothalamus: a new player in thermoregulation

2007 ◽  
Vol 292 (1) ◽  
pp. R47-R63 ◽  
Author(s):  
Joseph A. DiMicco ◽  
Dmitry V. Zaretsky
Keyword(s):  
Sympathetic Nerve Activity ◽  
Core Body Temperature ◽  
Central Administration ◽  
Dorsomedial Hypothalamus ◽  
Brown Adipose ◽  
Significant Difference ◽  
Raphe Pallidus ◽  
Core Body ◽  
The Brain ◽  
Cutaneous Vasoconstriction

Neurons in the dorsomedial hypothalamus (DMH) play key roles in physiological responses to exteroceptive (“emotional”) stress in rats, including tachycardia. Tachycardia evoked from the DMH or seen in experimental stress in rats is blocked by microinjection of the GABAA receptor agonist muscimol into the rostral raphe pallidus (rRP), an important thermoregulatory site in the brain stem, where disinhibition elicits sympathetically mediated activation of brown adipose tissue (BAT) and cutaneous vasoconstriction in the tail. Disinhibition of neurons in the DMH also elevates core temperature in conscious rats and sympathetic activity to least significant difference interscapular BAT (IBAT) and IBAT temperature in anesthetized preparations. The latter effects are blocked by microinjection of muscimol into the rRP, while microinjection of muscimol into either the rRP or DMH suppresses increases in sympathetic nerve activity to IBAT, IBAT temperature, and core body temperature elicited either by microinjection of PGE2 into the preoptic area (an experimental model for fever), or central administration of fentanyl. Neurons concentrated in the dorsal region of the DMH project directly to the rRP, a location corresponding to that of neurons transsynaptically labeled from IBAT. Thus these neurons control nonshivering thermogenesis in rats, and their activation signals its recruitment in diverse experimental paradigms. Evidence also points to a role for neurons in the DMH in thermoregulatory cutaneous vasoconstriction, shivering, and endocrine adjustments. These directions provide intriguing avenues for future exploration that may expand our understanding of the DMH as an important hypothalamic site for the integration of autonomic, endocrine, and behavioral responses to diverse challenges.

Central and Peripheral Clock Control of Circadian Feeding Rhythms

2021 ◽  
pp. 074873042110458
Author(s):  
Carson V. Fulgham ◽  
Austin P. Dreyer ◽  
Anita Nasseri ◽  
Asia N. Miller ◽  
Jacob Love ◽  
...  
Keyword(s):  
Locomotor Activity ◽  
Circadian Clock ◽  
Feeding Behavior ◽  
Molecular Clock ◽  
Fat Body ◽  
Molecular Clocks ◽  
Central Brain ◽  
Feeding Rhythms ◽  
Free Running ◽  
The Brain

Many behaviors exhibit ~24-h oscillations under control of an endogenous circadian timing system that tracks time of day via a molecular circadian clock. In the fruit fly, Drosophila melanogaster, most circadian research has focused on the generation of locomotor activity rhythms, but a fundamental question is how the circadian clock orchestrates multiple distinct behavioral outputs. Here, we have investigated the cells and circuits mediating circadian control of feeding behavior. Using an array of genetic tools, we show that, as is the case for locomotor activity rhythms, the presence of feeding rhythms requires molecular clock function in the ventrolateral clock neurons of the central brain. We further demonstrate that the speed of molecular clock oscillations in these neurons dictates the free-running period length of feeding rhythms. In contrast to the effects observed with central clock cell manipulations, we show that genetic abrogation of the molecular clock in the fat body, a peripheral metabolic tissue, is without effect on feeding behavior. Interestingly, we find that molecular clocks in the brain and fat body of control flies gradually grow out of phase with one another under free-running conditions, likely due to a long endogenous period of the fat body clock. Under these conditions, the period of feeding rhythms tracks with molecular oscillations in central brain clock cells, consistent with a primary role of the brain clock in dictating the timing of feeding behavior. Finally, despite a lack of effect of fat body selective manipulations, we find that flies with simultaneous disruption of molecular clocks in multiple peripheral tissues (but with intact central clocks) exhibit decreased feeding rhythm strength and reduced overall food intake. We conclude that both central and peripheral clocks contribute to the regulation of feeding rhythms, with a particularly dominant, pacemaker role for specific populations of central brain clock cells.

Central administration of alpha-MSH antiserum augments fever in the rabbit

1986 ◽  
Vol 250 (5) ◽  
pp. R803-R806 ◽  
Author(s):  
S. T. Shih ◽  
O. Khorram ◽  
J. M. Lipton ◽  
S. M. McCann
Keyword(s):  
Interleukin 1 ◽  
Rabbit Serum ◽  
Normal Rabbit Serum ◽  
Central Administration ◽  
Normal Body Temperature ◽  
Melanocyte Stimulating Hormone ◽  
Average Rise ◽  
The Brain ◽  
Antipyretic Action

alpha-Melanocyte-stimulating hormone (alpha-MSH) has a marked antipyretic action when given centrally or peripherally, and the concentration of this peptide within the septal region of the brain increases during fever. To assess the significance of endogenous central alpha-MSH in fever, antiserum was given to rabbits via a cannula implanted in the third cerebral ventricle. Each day for 3 days, the animals received 50 microliters of normal rabbit serum (NRS) or an equal volume of antiserum raised against alpha-MSH. Interleukin 1 (IL 1) was then injected intravenously to determine the effect of central immunoneutralization of alpha-MSH on the febrile response. Immunoneutralization markedly prolonged fever. The average rise in temperature and the area under the fever curve after IL 1 injection were also significantly increased. Antiserum treatment did not alter normal body temperature, and NRS had no effect on IL 1-induced fever. These results indicate that endogenous central alpha-MSH contributes to physiological limitation of fever and that the role of this peptide in temperature regulation is relevant to the febrile state but not to normothermia.

scholarly journals C60 Fullerene Prevents Restraint Stress-Induced Oxidative Disorders in Rat Tissues: Possible Involvement of the Nrf2/ARE-Antioxidant Pathway

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Olga O. Gonchar ◽  
Andriy V. Maznychenko ◽  
Nataliya V. Bulgakova ◽  
Inna V. Vereshchaka ◽  
Tomasz Tomiak ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Protein Expression ◽  
Restraint Stress ◽  
Stress Condition ◽  
Rat Tissues ◽  
Stress Exposure ◽  
The Brain ◽  
Nrf2 Protein

The effects of C60FAS (50 and 500 μg/kg) supplementation, in a normal physiological state and after restraint stress exposure, on prooxidant/antioxidant balance in rat tissues were explored and compared with the effects of the known exogenous antioxidant N-acetylcysteine. Oxidative stress biomarkers (ROS, O2⋅−, H2O2, and lipid peroxidation) and indices of antioxidant status (MnSOD, catalase, GPx, GST, γ-GCL, GR activities, and GSH level) were measured in the brain and the heart. In addition, protein expression of Nrf2 in the nuclear and cytosol fractions as well as the protein level of antiradical enzyme MnSOD and GSH-related enzymes γ-GCLC, GPx, and GSTP as downstream targets of Nrf2 was evaluated by western blot analysis. Under a stress condition, C60FAS attenuates ROS generation and O2⋅− and H2O2 releases and thus decreases lipid peroxidation as well as increases rat tissue antioxidant capacity. We have shown that C60FAS supplementation has dose-dependent and tissue-specific effects. C60FAS strengthened the antiradical defense through the upregulation of MnSOD in brain cells and maintained MnSOD protein content at the control level in the myocardium. Moreover, C60FAS enhanced the GSH level and the activity/protein expression of GSH-related enzymes. Correlation of these changes with Nrf2 protein content suggests that under stress exposure, along with other mechanisms, the Nrf2/ARE-antioxidant pathway may be involved in regulation of glutathione homeostasis. In our study, in an in vivo model, when C60FAS (50 and 500 μg/kg) was applied alone, no significant changes in Nrf2 protein expression as well as in activity/protein levels of MnSOD and GSH-related enzymes in both tissues types were observed. All these facts allow us to assume that in the in vivo model, C60FAS affects on the brain and heart endogenous antioxidative statuses only during the oxidative stress condition.

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