Center for Neurobiology of Stress

Sun City Center, United States

Center for Neurobiology of Stress

Sun City Center, United States
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Chen W.,Center for Neurobiology of Stress | Zhang G.,Center for Neurobiology of Stress | Marvizon J.C.G.,Center for Neurobiology of Stress | Marvizon J.C.G.,Veteran Affairs Greater Los Angeles Healthcare System
Neuroscience | Year: 2010

The function of N-methyl-d-aspartate (NMDA) receptors in primary afferents remains controversial, in particular regarding their ability to evoke substance P release in the spinal cord. The objective of this study was, first, to confirm that substance P release evoked by NMDA is mediated by NMDA receptors in primary afferent terminals. Second, we investigated whether these NMDA receptors are inactivated in some conditions, which would explain why their effect on substance P release was not observed in some studies. Substance P release was induced in spinal cord slices and measured as neurokinin 1 (NK1) receptor internalization in lamina I neurons. NMDA (combined with d-serine) induced NK1 receptor internalization with a half of the effective concentration (EC50) of 258 nM. NMDA-induced NK1 receptor internalization was abolished by the NK1 receptor antagonist L-703,606, confirming that is was caused by substance P release, by NMDA receptor antagonists (MK1801 and ifenprodil), showing that it was mediated by NMDA receptors containing the NR2B subunit, and by preincubating the slices with capsaicin, showing that the substance P release was from primary afferents. However, it was not affected by lidocaine and ω-conotoxin MVIIA, which block Na+ channels and voltage-dependent Ca2+ channels, respectively. Therefore, NMDA-induced substance P release does not require firing of primary afferents or the opening of Ca2+ channels, which is consistent with the idea that NMDA receptors induce substance P directly by letting Ca2+ into primary afferent terminals. Importantly, NMDA-induced substance P release was eliminated by preincubating the slices for 1 h with the Src family kinase inhibitors PP1 and dasatinib, and was substantially increased by the protein tyrosine phosphatase inhibitor BVT948. In contrast, PP1 did not affect NK1 receptor internalization induced by capsaicin. These results show that tyrosine-phosphorylation of these NMDA receptors is regulated by the opposite actions of Src family kinases and protein tyrosine phosphatases, and is required to induce substance P release.

Mayer E.A.,Center for Neurobiology of Stress
Nature Reviews Neuroscience | Year: 2011

The concept that the gut and the brain are closely connected, and that this interaction plays an important part not only in gastrointestinal function but also in certain feeling states and in intuitive decision making, is deeply rooted in our language. Recent neurobiological insights into this gut-"brain crosstalk have revealed a complex, bidirectional communication system that not only ensures the proper maintenance of gastrointestinal homeostasis and digestion but is likely to have multiple effects on affect, motivation and higher cognitive functions, including intuitive decision making. Moreover, disturbances of this system have been implicated in a wide range of disorders, including functional and inflammatory gastrointestinal disorders, obesity and eating disorders. © 2011 Macmillan Publishers Limited. All rights reserved.

Saito Y.A.,Mayo Medical School | Mitra N.,University of Pennsylvania | Mayer E.A.,Center for Neurobiology of Stress
Gastroenterology | Year: 2010

Functional gastrointestinal disorders are complex symptom-based disorders without agreed upon biomarkers or pathophysiology. A better understanding of the genetic architecture of these disorders would help to better identify their complex biology and explain the common comorbidity with other disorders of persistent pain, mood, and affect, as well as possibly make it possible to identify subgroups of patients who respond to customized therapies. In contrast to monogenic diseases, polygenic diseases and traits are characterized by the contribution of common variants in a large number of genes, as well as environmental factors, to the vulnerability of an individual. Family and twin studies have clearly established a genetic component in irritable bowel syndrome. Although candidate gene studies have identified a few gene polymorphisms that may be correlated with the syndrome, small sample size, lack of reproducibility in large data sets, and the unreliability of the clinical phenotype require caution when extrapolating to a major role of any of the reported polymorphisms in the pathophysiology of irritable bowel syndrome. Future progress in this area will require better characterization of intermediate phenotypes with large effect size for the clinical phenotype, as well as consideration of gene-gene, environment-gene (epigenetics), and sex-gene interactions, genome-wide association, and whole genome sequencing approaches in large data sets. © 2010 AGA Institute.

Stengel A.,University of California at Los Angeles | Wang L.,University of California at Los Angeles | Goebel-Stengel M.,University of California at Los Angeles | Tache Y.,University of California at Los Angeles | Tache Y.,Center for Neurobiology of Stress
NeuroReport | Year: 2011

Kisspeptin is distributed not only in brain areas for regulating reproduction but also in nuclei involved in feeding control. Whether kisspeptin alters food intake is unknown in mice. We examined how kisspeptin-10 influences feeding after intracerebroventricular injection in mice using automated monitoring. Kisspeptin-10 (0.3, 1, and 3 μg/mouse) dose-dependently inhibited the feeding response to an overnight fast by 50, 95, and 90% respectively, during the 2-3 h period postinjection. The 1μg/mouse dose reduced the 4-h cumulative food intake by 28% whereas intraperitoneal injection (10 μg/mouse) did not. The decreased 4-h food intake was due to reduced meal frequency (-45%/4 h), whereas meal size and gastric emptying were not altered. These data suggest that kisspeptin may be a negative central regulator of feeding by increasing satiety. © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins.

Stengel A.,Charité - Medical University of Berlin | Tache Y.,University of California at Los Angeles | Tache Y.,Center for Neurobiology of Stress
Frontiers in Neuroscience | Year: 2014

Early on, corticotropin-releasing factor (CRF), a hallmark brain peptide mediating many components of the stress response, was shown to affect food intake inducing a robust anorexigenic response when injected into the rodent brain. Subsequently, other members of the CRF signaling family have been identified, namely urocortin (Ucn) 1, Ucn 2, and Ucn 3 which were also shown to decrease food intake upon central or peripheral injection. However, the kinetics of feeding suppression was different with an early decrease following intracerebroventricular injection of CRF and a delayed action of Ucns contrasting with the early onset after systemic injection. CRF and Ucns bind to two distinct G-protein coupled membrane receptors, the CRF1 and CRF2. New pharmacological tools such as highly selective peptide CRF1 or CRF2 agonists or antagonists along with genetic knock-in or knock-out models have allowed delineating the primary role of CRF2 involved in the anorexic response to exogenous administration of CRF and Ucns. Several stressors trigger behavioral changes including suppression of feeding behavior which are mediated by brain CRF receptor activation. The present review will highlight the state-of-knowledge on the effects and mechanisms of action of CRF/Ucns-CRF1/2 signaling under basal conditions and the role in the alterations of food intake in response to stress. © 2014 Stengel and Taché.

Mayer E.A.,Center for Neurobiology of Stress | Mayer E.A.,University of California at Los Angeles | Tillisch K.,Center for Neurobiology of Stress | Tillisch K.,University of California at Los Angeles
Annual Review of Medicine | Year: 2011

The importance of bidirectional brain-gut interactions in gastrointestinal (GI) illness is increasingly recognized, most prominently in the area of functional GI syndromes such as irritable bowel syndrome (IBS), functional dyspepsia, and functional chest pain. The brain receives a constant stream of interoceptive input from the GI tract, integrates this information with other interoceptive information from the body and with contextual information from the environment, and sends an integrated response back to various target cells within the GI tract. This system is optimized to assure homeostasis of the GI tract during physiological perturbations and to adapt GI function to the overall state of the organism. In health, the great majority of interoceptive information reaching the brain is not consciously perceived but serves primarily as input to autonomic reflex pathways. In patients with functional abdominal pain syndromes, conscious perception of interoceptive information from the GI tract, or recall of interoceptive memories of such input, can occur in the form of constant or recurrent discomfort or pain. This is often associated with alterations in autonomic nervous system output and with emotional changes. A model is proposed that incorporates reported peripheral and central abnormalities in patients with IBS, extrapolates similar alterations in brain-gut interactions to patients with other chronic abdominal pain syndromes, and provides novel treatment targets. © 2011 by Annual Reviews. All rights reserved.

Kilpatrick L.A.,University of California at Los Angeles | Kilpatrick L.A.,Center for Neurobiology of Stress | Labus J.S.,University of California at Los Angeles | Coveleskie K.,University of California at Los Angeles | And 9 more authors.
Gastroenterology | Year: 2011

Background & Aims: 5-Hydroxytryptamine (5-HT)3 receptor (5-HT 3R) antagonists are effective in treating patients with irritable bowel syndrome (IBS) and have anxiolytic effects. Their therapeutic effects are related, in part, to reducing amygdala engagement during expected visceral pain. A single nucleotide polymorphism in HTR3A, c.-42C>T;(C178T; rs1062613), is associated with altered reactivity of the amygdala during emotional face processing in healthy subjects (controls). We evaluated the influence of this single nucleotide polymorphism on amygdala reactivity to emotional faces and nonemotional stimuli in female patients with IBS and controls. Methods: We measured brain responses during an affect-matching paradigm in 54 women (26 with IBS, 29 controls) using functional magnetic resonance imaging. We examined associations between HTR3A c.-42C>T genotype (C/C vs T carrier) and responses in amygdala and other regions of brain that expressed high levels of 5-HT 3R. Results: The C/C genotype was associated with greater anxiety symptoms in patients with IBS and controls and increased activation of the amygdala under emotional and nonemotional conditions. Among patients with IBS, C/C genotype was associated with greater symptom ratings. A subset of IBS patients with the C/C genotype had increased amygdala responses to nonemotional stimuli, compared with other subjects with C/C genotype. Conclusions: Regardless of diagnosis, the C/C genotype of the c.-42C>T polymorphism in HTR3A, compared with T carrier status, is associated with increased anxiety and amygdala responsiveness during emotional and nonemotional tasks. This polymorphism was associated with severity of IBS symptoms. Although this genotype is not sufficient for diagnosis of IBS, it is associated with severity of symptoms. © 2011 AGA Institute.

Seminowicz D.A.,McGill University | Labus J.S.,Center for Neurobiology of Stress | Bueller J.A.,Center for Neurobiology of Stress | Tillisch K.,Center for Neurobiology of Stress | And 3 more authors.
Gastroenterology | Year: 2010

Background & Aims: Several studies have examined structural brain changes associated with chronic pain syndromes, including irritable bowel syndrome (IBS), but study sample sizes have been small and heterogeneous. Methods: We used magnetic resonance imaging-based techniques, voxel-based morphometry, and cortical thickness analysis to examine brain anatomical differences in a relatively large, tightly screened sample of IBS patients (n = 55); we compared data with that from healthy persons (controls; n = 48). Results: IBS was associated with decreased gray matter density (GMD) in widespread areas of the brain, including medial prefrontal and ventrolateral prefrontal cortex, posterior parietal cortex, ventral striatum, and thalamus. Compared with controls, we observed increased GMD in patients with IBS in the pregenual anterior cingulate cortex and the orbitofrontal cortex, as well as trends in the posterior insula/secondary somatosensory cortex, (para)hippocampus, and left dorsolateral prefrontal cortex. In accounting for anxiety and depression, we found that several of the regions involved in affective processing no longer differed between patients with IBS and controls, whereas the differences in prefrontal and posterior parietal cortices remained. The areas of decreased GMD associated with IBS were largely consistent across clinical subgroups, based on predominant bowel habit and pain predominance of symptoms. No overall or regional differences were observed in cortical thickness between patients with IBS and controls. Conclusions: Changes in density of gray matter among regions involved in cognitive/evaluative functions are specifically observed in patients with IBS, whereas changes in other areas of the brain can be explained by levels of anxiety and depression. © 2010 AGA Institute.

Stengel A.,Center for Neurobiology of Stress | Coskun T.,Eli Lilly and Company | Goebel M.,Center for Neurobiology of Stress | Wang L.,Center for Neurobiology of Stress | And 4 more authors.
Endocrinology | Year: 2010

Somatostatin and octreotide injected into the brain have been reported to modulate food intake. However, little is known regarding the underlying mechanisms. The stable oligosomatostatin analog, des-AA1,2,4,5,12,13- [DTrp8]-somatostatin (ODT8-SST), like somatostatin, binds to all five somatostatin receptors (sst1-5). We characterized the effects of ODT8-SST injected intracerebroventricularly (icv) on food consumption and related mechanisms of action in freely fed rats. ODT8-SST (0.3 and 1 μg per rat, icv) injected during the light or dark phase induced an early onset (within 1 h) and long-lasting (4 h) increase in food intake in nonfasted rats. By contrast, ip injection (0.3-3 mg/kg) or icv injection of selective sst 1 or sst4 agonists (1 μg per rat) had no effect. The 2 h food intake response during the light phase was blocked by icv injection of a sst2 antagonist, the neuropeptide Y (NPY) Y1 receptor antagonist, BIBP-3226, and ip injection of the μ-opioid receptor antagonist, naloxone, and not associated with changes in plasma ghrelin levels. ODT8-SST (1 μg per rat, icv) stimulated gastric emptying of a solid meal which was also blocked by naloxone. The increased food intake was accompanied by a sustained increase in respiratory quotient, energy expenditure, and drinking as well as μ-opioid receptor-independent grooming behavior and hyperthermia, while ambulatory movements were not altered after ODT8-SST (1 μg per rat, icv). These data show that ODT8-SST acts primarily through brain sst2 receptors to induce a long-lasting orexigenic effect that involves the activation of Y1 and opiate-receptors, accompanied by enhanced gastric transit and energy expenditure suggesting a modulation of NPYergic and opioidergic orexigenic systems by brain sst2 receptors. Copyright © 2010 by The Endocrine Society.

Stengel A.,Center for Neurobiology of Stress | Goebel M.,Center for Neurobiology of Stress | Wang L.,Center for Neurobiology of Stress | Tache Y.,Center for Neurobiology of Stress | And 2 more authors.
Biochemical and Biophysical Research Communications | Year: 2010

The enzyme that acylates ghrelin was recently identified in mice as the fourth member of the membrane-bound O-acyltransferases superfamily (MBOAT4) and named ghrelin-O-acyltransferase (GOAT). Only one report showed GOAT mRNA expression in ghrelin-expressing cells of the mouse stomach. We investigated the distribution of GOAT protein in peripheral tissues and co-expression with endocrine markers in the gastric mucosa using a custom-made anti-GOAT antibody. Tissues were collected from male Sprague-Dawley rats and C57BL/6 mice. Western blot revealed two immunoreactive bands in rat and mouse gastric corpus mucosal proteins, a 50 kDa band corresponding to the GOAT protein and a 100 kDa band likely corresponding to a dimer. Western blot also detected GOAT in the plasma and levels were strongly increased after 24-h fasting in mice and slightly in rats. GOAT-immunoreactive cells were located in the gastric corpus mucosa and the anterior pituitary gland, whereas other peripheral tissues of rats and mice examined were negative. In mice, GOAT-immunoreactive cells were mainly distributed throughout the middle portion of the oxyntic glands, whereas in rats they were localized mainly in the lower portion of the glands. Double labeling showed that 95 ± 1% of GOAT-immunoreactive cells in mice co-labeled with ghrelin, whereas in rats only 56 ± 4% of GOAT-positive cells showed co-expression of ghrelin. The remainder of the GOAT-immunopositive cells in rats co-expressed histidine decarboxylase (44 ± 3%). No co-localization was observed with somatostatin in rats or mice. These data suggest species differences between rats and mice in gastric GOAT expression perhaps resulting in a different role of the MBOAT4 enzyme in the rat stomach. Detection of GOAT in the plasma raises the possibility that ghrelin octanoylation may occur in the circulation and the fasting-induced increase in GOAT may contribute to the increase of acylated ghrelin after fasting.

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