Alcohol preference in mice lacking the Avpr1a vasopressin receptor

2008 ◽  
Vol 294 (5) ◽  
pp. R1482-R1490 ◽  
Author(s):  
Atsushi Sanbe ◽  
Norio Takagi ◽  
Yoko Fujiwara ◽  
Junji Yamauchi ◽  
Toshiya Endo ◽  
...  
Keyword(s):  
Glutamate Release ◽  
Ethanol Consumption ◽  
Inhibitory Effect ◽  
Presynaptic Terminal ◽  
Behavioral Effects ◽  
Wild Type ◽  
Pressure Water ◽  
The Central Nervous System ◽  
Voluntary Ethanol Consumption

[Arg8]-vasopressin (Avp), a nonapeptide hormone, is known to regulate blood pressure, water balance, and a variety of behaviors such as anxiety, aggression, and bonding. Although some evidence that Avp modifies ethanol consumption and some of the effects of ethanol on behavior have been reported, the role of Avp in alcohol consumption and preference is poorly understood. The Avp1a receptor (Avpr1a) is ubiquitously expressed in the central nervous system. To determine the role of Avp signaling on the behavioral effects of alcohol, we examined voluntary ethanol consumption in mice with targeted disruptions of the Avpr1a knockout (Avpr1a KO) gene. Avpr1a KO mice displayed both increased ethanol consumption and preference compared with wild-type (WT) mice. Enhanced ethanol consumption was dramatically and reversibly reduced by treatment with N-methyl-d-aspartic acid antagonists. Basal glutamate release was elevated around the striatum in Avpr1a KO mice. Elevation of extracellular glutamate was also produced in WT mice by local application of an Avpr1a antagonist though a dialysis probe, and this elevation was quickly reversed by stopping the perfusion. These results suggest that Avp can inhibit the release of glutamate from the presynaptic terminal via the Avp1a receptor and that elevation of glutamate levels owing to loss of the inhibitory effect via Avp-Avpr1a signaling may play an important role in the preference for ethanol.

scholarly journals Proteolytic maturation of α2δ controls the probability of synaptic vesicular release

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Laurent Ferron ◽  
Ivan Kadurin ◽  
Annette C Dolphin
Keyword(s):  
Calcium Channels ◽  
Inhibitory Effect ◽  
Wild Type ◽  
Voltage Gated ◽  
Synaptic Release ◽  
Voltage Gated Calcium Channels ◽  
Vesicular Release ◽  
Active Zones ◽  
Asynchronous Release

Auxiliary α2δ subunits are important proteins for trafficking of voltage-gated calcium channels (CaV) at the active zones of synapses. We have previously shown that the post-translational proteolytic cleavage of α2δ is essential for their modulatory effects on the trafficking of N-type (CaV2.2) calcium channels (Kadurin et al., 2016). We extend these results here by showing that the probability of presynaptic vesicular release is reduced when an uncleaved α2δ is expressed in rat neurons and that this inhibitory effect is reversed when cleavage of α2δ is restored. We also show that asynchronous release is influenced by the maturation of α2δ−1, highlighting the role of CaV channels in this component of vesicular release. We present additional evidence that CaV2.2 co-immunoprecipitates preferentially with cleaved wild-type α2δ. Our data indicate that the proteolytic maturation increases the association of α2δ−1 with CaV channel complex and is essential for its function on synaptic release.

A probable role of dihydropyridine receptors in repression of Ca2+ sparks demonstrated in cultured mammalian muscle

2006 ◽  
Vol 290 (2) ◽  
pp. C539-C553 ◽  
Author(s):  
Jingsong Zhou ◽  
Jianxun Yi ◽  
Leandro Royer ◽  
Bradley S. Launikonis ◽  
Adom González ◽  
...  
Keyword(s):  
Ryanodine Receptors ◽  
Critical Role ◽  
Primary Cultures ◽  
Inhibitory Effect ◽  
Wild Type ◽  
Dihydropyridine Receptors ◽  
Skeletal Muscle Contraction ◽  
Probable Role ◽  
Emission Ratios

To activate skeletal muscle contraction, action potentials must be sensed by dihydropyridine receptors (DHPRs) in the T tubule, which signal the Ca2+ release channels or ryanodine receptors (RyRs) in the sarcoplasmic reticulum (SR) to open. We demonstrate here an inhibitory effect of the T tubule on the production of sparks of Ca2+ release. Murine primary cultures were confocally imaged for Ca2+ detection and T tubule visualization. After 72 h of differentiation, T tubules extended from the periphery for less than one-third of the myotube radius. Spontaneous Ca2+ sparks were found away from the region of cells where tubules were found. Immunostaining showed RyR1 and RyR3 isoforms in all areas, implying inhibition of both isoforms by a T tubule component. To test for a role of DHPRs in this inhibition, we imaged myotubes from dysgenic mice ( mdg) that lack DHPRs. These exhibited T tubule development similar to that of normal myotubes, but produced few sparks, even in regions where tubules were absent. To increase spark frequency, a high-Ca2+ saline with 1 mM caffeine was used. Wild-type cells in this saline plus 50 μM nifedipine retained the topographic suppression pattern of sparks, but dysgenic cells in high-Ca2+ saline did not. Shifted excitation and emission ratios of indo-1 in the cytosol or mag-indo-1 in the SR were used to image [Ca2+] in these compartments. Under the conditions of interest, wild-type and mdg cells had similar levels of free [Ca2+] in cytosol and SR. These data suggest that DHPRs play a critical role in reducing the rate of spontaneous opening of Ca2+ release channels and/or their susceptibility to Ca2+-induced activation, thereby suppressing the production of Ca2+ sparks.

Tissue specificity and physiological relevance of various isoforms of adenylyl cyclase

2000 ◽  
Vol 279 (3) ◽  
pp. F400-F416 ◽  
Author(s):  
Nicole Defer ◽  
Martin Best-Belpomme ◽  
Jacques Hanoune
Keyword(s):  
Adenylyl Cyclase ◽  
Inhibitory Effect ◽  
Relative Level ◽  
Extracellular Signals ◽  
Physiological Relevance ◽  
A Cell ◽  
The Central Nervous System ◽  
Cellular Transfection ◽  
G Protein Coupled

The present review focuses on the potential physiological regulations involving different isoforms of adenylyl cyclase (AC), the enzymatic activity responsible for the synthesis of cAMP from ATP. Depending on the properties and the relative level of the isoforms expressed in a tissue or a cell type at a specific time, extracellular signals received by the G protein-coupled receptors can be differently integrated. We report here on various aspects of such regulations, emphasizing the role of Ca2+/calmodulin in activating AC1 and AC8 in the central nervous system, the potential inhibitory effect of Ca2+ on AC5 and AC6, and the changes in the expression pattern of the isoforms during development. A particular emphasis is given to the role of cAMP during drug dependence. Present experimental limitations are also underlined (pitfalls in the interpretation of cellular transfection, scarcity of the invalidation models, and so on).

Triad1 Regulates Myelopoiesis through Different Ubiquitin Ligase Activities.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3292-3292
Author(s):  
Bert A. van der Reijden ◽  
Laurens van der Meer ◽  
Jurgen Marteijn ◽  
Theo de Witte ◽  
Joop H. Jansen
Keyword(s):  
Ubiquitin Ligase ◽  
Coiled Coil ◽  
Ring Finger ◽  
Proteasomal Degradation ◽  
Inhibitory Effect ◽  
Ring Domain ◽  
Wild Type ◽  
Ubiquitin Chain ◽  
Clonogenic Growth

Abstract The modification of cellular proteins with poly-ubiquitin chains plays an essential role in hematopoiesis. Different types of ubiquitin chains may have opposite effects on the marked proteins. Chains linked through lysine 48 of ubiquitin are recognized by the proteasome resulting in progressive degradation of the ubiquitylated proteins. Ubiquitin chains linked through lysine 63 are not recognized by the proteasome. Instead, these chains can bind proteins that regulate signal transduction and gene transcription. Although it is known that ubiquitylation is essential for hematopoiesis and that alterations in ubiquitylation have been implicated in malignant hematopoiesis the ubiquitin ligases that catalyze protein ubiquitylation remain largely unknown. Triad1 is an ubiquitin ligase that inhibits the proliferation of myeloid progenitor cells through its ligase activity. Triad1 belongs to a unique class of ligases that harbor two RING finger protein domains. This domain specifically binds ubiquitin conjugating enzymes (Ubcs). Together with the Ubcs the ligases determine which type of ubiquitin chain is catalyzed. To understand how Triad1 regulates myelopoiesis we screened a panel of Ubcs for Triad1 interaction and found that Triad1 binds UbcH7 through its N-terminal RING domain and Ubc13 through its C-terminal RING domain. UbcH7 catalyzes the formation of ubiquitin chains linked through lysine 48 that are recognized by the proteasome. Importantly, ubiquitin chains catalyzed by Ubc13 are linked through lysine 63 and are not recognized by the proteasome. In agreement with these interactions, in vitro ubiquitylation assays using different ubiquitin mutants containing only one lysine residue showed that Triad1 can catalyze the formation of both types of ubiquitin chains. The relevance of these findings in myelopoiesis was studied by generating a panel of Triad1 deletion mutants that lack the coiled coil, DRIL or RING domains. Next, the growth inhibitory effect of these mutants was tested in clonogenic assays by retroviral transduction of U937 cells. Like in primary cells, wild type Triad1 inhibited U937 colony formation by over 60% compared to empty vector transduced cells. Three Triad1 mutants lacking the DRIL domain or either one or two of the coiled coil domains inhibited clonogenic growth at a comparable rate as wild type Triad1. In contrast, deletion of either the N- or C-terminal RING finger completely abrogated the inhibitory effect of Triad1 in clonogenic growth. Thus, loss of either the UbcH7 or Ubc13 binding domain of Triad1 affects its inhibitory function in myeloid cell proliferation. Recently, we reported that Triad1 binds the transcription factor Gfi1. Gfi1 plays an important role during many hematopoietic developmental stages and is essential for neutrophilic differentiation. Remarkably, Triad1 inhibited Gfi1 ubiquitylation and proteasomal degradation. The finding here that Triad1 can catalyze the formation of different ubiquitin chains might suggest that Triad1 may modify Gfi1 with ubiquitin in a functional way, rather than marking it for proteasomal degradation. Indeed, in vivo ubiquitylation experiments showed that Gfi1 can be modified with ubiquitin chains not linked through lysine 48. The relevance of this finding and the role of Triad1 in this process is currently studied. Together, these data indicate that the dual ubiquitin ligase activity that results in the formation of different poly-ubiquitin chains is crucial to the central role of Triad1 in myelopoiesis.

p21Waf1 deficiency does not decrease DNA repair in E1A+cHa-Ras transformed cells by HDI sodium butyrate

2018 ◽  
Vol 399 (11) ◽  
pp. 1297-1304
Author(s):  
Maria Igotti ◽  
Olga Gnedina ◽  
Alisa Morshneva ◽  
Svetlana Svetlikova ◽  
Valery Pospelov
Keyword(s):  
Dna Repair ◽  
Sodium Butyrate ◽  
Inhibitory Effect ◽  
Genome Integrity ◽  
Transformed Cells ◽  
Wild Type ◽  
Γh2ax Foci ◽  
Deacetylase Inhibitor ◽  
Host Cell Reactivation

AbstractThis study aimed to explore a role of p21Waf1 in γH2AX foci formation and DNA repair as assessed by a Host-Cell Reactivation Assay in wild-type (p21Waf+/+) and p21Waf1-deficient E1A+Ras-transformed cells. p21Waf1+/+cells have low γH2AX background compared to p21Waf1−/−cells. The treatment with histone deacetylase inhibitor (HDI) sodium butyrate (NaBut) causes to accumulation of γH2AX in p21Waf+/+cells with little effect in p21Waf−/−cells. Moreover, NaBut inhibits DNA repair in wt cells but not in p21Waf1−/−cells. This could be explained by the weakening of GADD45 and PCNA proteins binding in NaBut-treated p21Waf1-expressing cells but not in p21Waf1−/−cells. We suggest that in wt-ERas cells NaBut activates both p21Waf1 expression and a release of p21Waf1 from the complexes with E1A that leads to suppression of DNA repair and promotes γH2AX persistency. The absence of p21Waf1 is by itself considered by the cell as stressful factor with formation of γH2AX. But the lack of p21Waf1 interferes with an inhibitory effect of NaBut to inhibit DNA repair and thereby to stop concomitant accumulation of harmful mutations. We conclude that p21Waf1 is directly involved in control of genome integrity and DNA repair acting through modulation of the components of the DNA repair machinery.

scholarly journals Pathogenesis of Chimeric MHV4/MHV-A59 Recombinant Viruses: the Murine Coronavirus Spike Protein Is a Major Determinant of Neurovirulence

1999 ◽  
Vol 73 (9) ◽  
pp. 7752-7760 ◽  
Author(s):  
Joanna J. Phillips ◽  
Ming Ming Chua ◽  
Ehud Lavi ◽  
Susan R. Weiss
Keyword(s):  
Hepatitis Virus ◽  
Major Determinant ◽  
Rna Recombination ◽  
Wild Type ◽  
Recombinant Viruses ◽  
S Gene ◽  
The Central Nervous System ◽  
Plaque Phenotype ◽  
The Brain

ABSTRACT The mouse hepatitis virus (MHV) spike glycoprotein, S, has been implicated as a major determinant of viral pathogenesis. In the absence of a full-length molecular clone, however, it has been difficult to address the role of individual viral genes in pathogenesis. By using targeted RNA recombination to introduce the S gene of MHV4, a highly neurovirulent strain, into the genome of MHV-A59, a mildly neurovirulent strain, we have been able to directly address the role of the S gene in neurovirulence. In cell culture, the recombinants containing the MHV4 S gene, S4R22 and S4R21, exhibited a small-plaque phenotype and replicated to low levels, similar to wild-type MHV4. Intracranial inoculation of C57BL/6 mice with S4R22 and S4R21 revealed a marked alteration in pathogenesis. Relative to wild-type control recombinant viruses (wtR13 and wtR9), containing the MHV-A59 S gene, the MHV4 S gene recombinants exhibited a dramatic increase in virulence and an increase in both viral antigen staining and inflammation in the central nervous system. There was not, however, an increase in the level of viral replication in the brain. These studies demonstrate that the MHV4 S gene alone is sufficient to confer a highly neurovirulent phenotype to a recombinant virus deriving the remainder of its genome from a mildly neurovirulent virus, MHV-A59. This definitively confirms previous findings, suggesting that the spike is a major determinant of pathogenesis.

scholarly journals Competition between the Yops of Yersinia enterocolitica for Delivery into Eukaryotic Cells: Role of the SycE Chaperone Binding Domain of YopE

2000 ◽  
Vol 182 (17) ◽  
pp. 4811-4821 ◽  
Author(s):  
Aoife P. Boyd ◽  
Isabelle Lambermont ◽  
Guy R. Cornelis
Keyword(s):  
Binding Site ◽  
In Vitro Release ◽  
Inhibitory Effect ◽  
Binding Domain ◽  
Eukaryotic Cells ◽  
Target Cells ◽  
Wild Type ◽  
Animal Cells

ABSTRACT A type III secretion-translocation system allowsYersinia adhering at the surface of animal cells to deliver a cocktail of effector Yops (YopH, -O, -P, -E, -M, and -T) into the cytosol of these cells. Residues or codons 1 to 77 contain all the information required for the complete delivery of YopE into the target cell (release from the bacterium and translocation across the eukaryotic cell membrane). Residues or codons 1 to 15 are sufficient for release from the wild-type bacterium under Ca2+-chelating conditions but not for delivery into target cells. Residues 15 to 50 comprise the binding domain for SycE, a chaperone specific for YopE that is necessary for release and translocation of full-length YopE. To understand the role of this chaperone, we studied the delivery of YopE-Cya reporter proteins and YopE deletants by polymutant Yersinia devoid of most of the Yop effectors (ΔHOPEM and ΔTHE strains). We first tested YopE-Cya hybrid proteins and YopE proteins deleted of the SycE-binding site. In contrast to wild-type strains, these mutants delivered YopE15-Cya as efficiently as YopE130-Cya. They were also able to deliver YopEΔ17–77. SycE was dispensable for these deliveries. These results show that residues or codons 1 to 15 are sufficient for delivery into eukaryotic cells and that there is no specific translocation signal in Yops. However, the fact that the SycE-binding site and SycE were necessary for delivery of YopE by wild-type Yersinia suggests that they could introduce hierarchy among the effectors to be delivered. We then tested a YopE-Cya hybrid and YopE proteins deleted of amino acids 2 to 15 but containing the SycE-binding domain. These constructs were neither released in vitro upon Ca2+ chelation nor delivered into cells by wild-type or polymutant bacteria, casting doubts on the hypothesis that SycE could be a secretion pilot. Finally, it appeared that residues 50 to 77 are inhibitory to YopE release and that binding of SycE overcomes this inhibitory effect. Removal of this domain allowed in vitro release and delivery in cells in the absence as well as in the presence of SycE.

scholarly journals Corticotropin Releasing Factor Type 1 and 2 Receptor Signaling in the Medial Prefrontal Cortex Modulates Binge-Like Ethanol Consumption in C57BL/6J Mice

2019 ◽  
Vol 9 (7) ◽  
pp. 171 ◽  
Author(s):  
Stacey L. Robinson ◽  
Carlos A. Perez-Heydrich ◽  
Todd E. Thiele
Keyword(s):  
Prefrontal Cortex ◽  
Medial Prefrontal Cortex ◽  
Ethanol Consumption ◽  
Inhibitory Effect ◽  
Ethanol Intake ◽  
Corticotropin Releasing Factor ◽  
Factor Type ◽  
Drinking In The Dark

Corticotropin releasing factor (CRF) signaling via limbic CRF1 and 2 receptors (CRF1R and CRF2R, respectively) is known to modulate binge-like ethanol consumption in rodents. Though CRF signaling in the medial prefrontal cortex (mPFC) has been shown to modulate anxiety-like behavior and ethanol seeking, its role in binge ethanol intake is unknown. Here, we used “drinking-in-the-dark” (DID) procedures in male and female C57BL/6J mice to address this gap in the literature. First, the role of CRF1R and CRF2R signaling in the mPFC on ethanol consumption was evaluated through site-directed pharmacology. Next, we evaluated if CRF1R antagonist reduction of binge-intake was modulated in part through CRF2R activation by co-administration of a CRF1R and CRF2R antagonist. Intra-mPFC inhibition of CRF1R and activation of CRF2R resulted in decreased binge-like ethanol intake. Further, the inhibitory effect of the CRF1R antagonist was attenuated by co-administration of a CRF2R antagonist. We provide novel evidence that (1) inhibition of CRF1R or activation of CRF2R in the mPFC reduces binge-like ethanol intake; and (2) the effect of CRF1R antagonism may be mediated via enhanced CRF2R activation. These observations provide the first direct behavioral pharmacological evidence that CRF receptor activity in the mPFC modulates binge-like ethanol consumption.

Loss of cholecystokinin and glucagon-like peptide-1-induced satiation in mice lacking serotonin 2C receptors

2009 ◽  
Vol 296 (1) ◽  
pp. R51-R56 ◽  
Author(s):  
Lori Asarian
Keyword(s):  
Neural Mechanisms ◽  
Wild Type ◽  
Gut Peptides ◽  
Serotonin Signaling ◽  
The Central Nervous System ◽  
Fos Expression ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
The Brain

To investigate the role of serotonin 2C receptors (2CR), which are expressed only in the central nervous system, in the satiating actions of the gut peptides CCK and glucagon-like peptide 1 (GLP-1), we examined 1) the effect of null mutations of serotonin 2CR (2CR KO) on the eating-inhibitory potencies of dark-onset intraperitoneal injections of 0.9, 1.7, or 3.5 nmol/kg (1, 2, or 4 μg/kg) CCK and 100, 200, and 400 nmol/kg (33, 66, or 132 μg/kg) GLP-1, and 2) the effects of intraperitoneal injections of 1.7 nmol//kg CCK and 100 nmol/kg GLP-1 on neuronal activation in the brain, as measured by c-Fos expression. All CCK and GLP-1 doses decreased 30-min food intake in wild-type (WT) mice, but none of them did in 2CR KO mice. CCK increased the number of cells expressing c-Fos in the nucleus tractus solitarii (NTS) of WT, but not 2CR KO mice. CCK induced similar degrees of c-Fos expression in the paraventricular (PVN) and arcuate (Arc) nuclei of the hypothalamus of both genotypes. GLP-1, on the other hand, increased c-Fos expression similarly in the NTS of both genotypes and increased c-Fos expression more in the PVN and Arc of 2CR KO mice, but not WT mice. These results indicate that serotonin signaling via serotonin 2CR is necessary for the full satiating effects of CCK and GLP-1. In addition, they suggest that the satiating effects of the two peptides are mediated by different neural mechanisms.

scholarly journals Dual Role of Cysteine 172 in Redox Regulation of Ribulose 1,5-Bisphosphate Carboxylase/Oxygenase Activity and Degradation

2003 ◽  
Vol 185 (5) ◽  
pp. 1509-1517 ◽  
Author(s):  
Yehouda Marcus ◽  
Hagit Altman-Gueta ◽  
Aliza Finkler ◽  
Michael Gurevitz
Keyword(s):  
Redox Regulation ◽  
Inhibitory Effect ◽  
Cysteine Residues ◽  
Wild Type ◽  
Bisphosphate Carboxylase ◽  
Enzyme Form ◽  
Oxygenase Activity ◽  
In The Wild ◽  
Cross Links

ABSTRACT Alkylation and oxidation of cysteine residues significantly decrease the catalytic activity and stimulate the degradation of ribulose 1,5-bisphosphate carboxylase/oxygenase (RuBisCO). We analyzed the role of vicinal cysteine residues in redox regulation of RuBisCO from Synechocystis sp. strain PCC 6803. Cys172 and Cys192, which are adjacent to the catalytic site, and Cys247, which cross-links two large subunits, were replaced by alanine. Whereas all mutant cells (C172A, C192A, C172A-C192A, and C247A) and the wild type grew photoautotrophically at similar rates, the maximal photosynthesis rates of C172A mutants decreased 10 to 20% as a result of 40 to 60% declines in RuBisCO turnover number. Replacement of Cys172, but not replacement of Cys192, prominently decreased the effect of cysteine alkylation or oxidation on RuBisCO. Oxidants that react with vicinal thiols had a less inhibitory effect on the activity of either the C172A or C192A enzyme variants, suggesting that a disulfide bond was formed upon oxidation. Thiol oxidation induced RuBisCO dissociation into subunits. This effect was either reduced in the C172A and C192A mutant enzymes or eliminated by carboxypentitol bisphosphate (CPBP) binding to the activated enzyme form. The CPBP effect presumably resulted from a conformational change in the carbamylated CPBP-bound enzyme, as implied from an alteration in the electrophoretic mobility. Stress conditions, provoked by nitrate deprivation, decreased the RuBisCO contents and activities in the wild type and in the C192A and C247A mutants but not in the C172A and C172A-C192A mutants. These results suggest that although Cys172 does not participate in catalysis, it plays a role in redox regulation of RuBisCO activity and degradation.

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