Status epilepticus induced by pentylenetetrazole modulates in vivo [11C]Ro 15-1788 binding to benzodiazepine receptors. Effects of ligands acting at the supramolecular receptor complex

1988 ◽  
Vol 146 (2-3) ◽  
pp. 207-214 ◽  
Author(s):  
C. Chavoix ◽  
Ph. Hantraye ◽  
E. Brouillet ◽  
B. Guibert ◽  
H. Fukuda ◽  
...  
Keyword(s):  
Status Epilepticus ◽  
Benzodiazepine Receptors ◽  
Receptor Complex

scholarly journals TGFβ signalling acts as a molecular brake of myoblast fusion

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Julie Melendez ◽  
Daniel Sieiro ◽  
David Salgado ◽  
Valérie Morin ◽  
Marie-Julie Dejardin ◽  
...  
Keyword(s):  
Dynamic Control ◽  
Muscle Growth ◽  
Myoblast Fusion ◽  
In Vivo Studies ◽  
In Vitro Assays ◽  
Receptor Complex ◽  
Tgfβ Signalling ◽  
Molecular Brake

AbstractFusion of nascent myoblasts to pre-existing myofibres is critical for skeletal muscle growth and repair. The vast majority of molecules known to regulate myoblast fusion are necessary in this process. Here, we uncover, through high-throughput in vitro assays and in vivo studies in the chicken embryo, that TGFβ (SMAD2/3-dependent) signalling acts specifically and uniquely as a molecular brake on muscle fusion. While constitutive activation of the pathway arrests fusion, its inhibition leads to a striking over-fusion phenotype. This dynamic control of TGFβ signalling in the embryonic muscle relies on a receptor complementation mechanism, prompted by the merging of myoblasts with myofibres, each carrying one component of the heterodimer receptor complex. The competence of myofibres to fuse is likely restored through endocytic degradation of activated receptors. Altogether, this study shows that muscle fusion relies on TGFβ signalling to regulate its pace.

scholarly journals High Natural Permissivity of Primary Rabbit Cells for HIV-1, with a Virion Infectivity Defect in Macrophages as the Final Replication Barrier

2010 ◽  
Vol 84 (23) ◽  
pp. 12300-12314 ◽  
Author(s):  
Hanna-Mari Tervo ◽  
Oliver T. Keppler
Keyword(s):  
T Cells ◽  
Late Phase ◽  
Small Animal ◽  
Receptor Complex ◽  
Restriction Factors ◽  
Cyclin T1 ◽  
Primary Rabbit ◽  
Species Specific ◽  
Hiv 1

ABSTRACT An immunocompetent, permissive, small-animal model would be valuable for the study of human immunodeficiency virus type 1 (HIV-1) pathogenesis and for the testing of drug and vaccine candidates. However, the development of such a model has been hampered by the inability of primary rodent cells to efficiently support several steps of the HIV-1 replication cycle. Although transgenesis of the HIV receptor complex and human cyclin T1 have been beneficial, additional late-phase blocks prevent robust replication of HIV-1 in rodents and limit the range of in vivo applications. In this study, we explored the HIV-1 susceptibility of rabbit primary T cells and macrophages. Envelope-specific and coreceptor-dependent entry of HIV-1 was achieved by expressing human CD4 and CCR5. A block of HIV-1 DNA synthesis, likely mediated by TRIM5, was overcome by limited changes to the HIV-1 gag gene. Unlike with mice and rats, primary cells from rabbits supported the functions of the regulatory viral proteins Tat and Rev, Gag processing, and the release of HIV-1 particles at levels comparable to those in human cells. While HIV-1 produced by rabbit T cells was highly infectious, a macrophage-specific infectivity defect became manifest by a complex pattern of mutations in the viral genome, only part of which were deamination dependent. These results demonstrate a considerable natural HIV-1 permissivity of the rabbit species and suggest that receptor complex transgenesis combined with modifications in gag and possibly vif of HIV-1 to evade species-specific restriction factors might render lagomorphs fully permissive to infection by this pathogenic human lentivirus.

In vivo imaging of brain lesions with [11C]CLINME, a new PET radioligand of peripheral benzodiazepine receptors

Glia ◽  
2007 ◽  
Vol 55 (14) ◽  
pp. 1459-1468 ◽  
Author(s):  
Hervé Boutin ◽  
Fabien Chauveau ◽  
Cyrille Thominiaux ◽  
Bertrand Kuhnast ◽  
Marie-Claude Grégoire ◽  
...  
Keyword(s):  
In Vivo Imaging ◽  
Benzodiazepine Receptors ◽  
Brain Lesions ◽  
Peripheral Benzodiazepine Receptors

THE BINDING OF [1,2-3H]TESTOSTERONE WITHIN NUCLEI OF THE RAT PROSTATE

1969 ◽  
Vol 44 (3) ◽  
pp. 323-333 ◽  
Author(s):  
W. I. P. MAINWARING
Keyword(s):  
Molecular Weight ◽  
Equilibrium Dialysis ◽  
Prostate Gland ◽  
Ventral Prostate ◽  
Rat Tissues ◽  
Receptor Complex ◽  
Rat Prostate ◽  
Binding Component

SUMMARY The specificity of the binding of [1,2-3H]testosterone to nuclei of various rat tissues in vivo has been studied. A significant amount of radioactivity was retained in the nuclei of androgen-dependent tissues only, particularly the ventral prostate gland. The bound radioactivity was only partially recovered as [1,2-3H]testosterone; the remainder was identified as [3H]5α-dihydrotestosterone. Efforts were made to characterize the binding component, or 'receptor', in prostatic nuclei. On digestion of nuclei labelled in vivo with [1,2-3H]testosterone, with enzymes of narrow substrate specificity, only trypsin released tritium, suggesting that the receptor is a protein. On the basis of subfractionation studies of labelled nuclei, the receptor is an acidic protein. The androgen—receptor complex could be effectively extracted from the prostatic nuclei in 1 m-NaCl and from the results of fractionations on a calibrated agarose column, the complex has a molecular weight 100,000–120,000. The specificity of the binding of steroids to such 1 m-NaCl extracts in vitro was investigated by the equilibrium dialysis procedure. Under these conditions, the specificity of the binding of [1,2-3H]testosterone demonstrated in vivo could not be simulated. The receptor is probably part of the chromatin complex but its precise intranuclear localization cannot be determined by biochemical procedures alone.

scholarly journals In Vivo Imaging of Peripheral Benzodiazepine Receptors in Mouse Lungs: A Biomarker of Inflammation

2005 ◽  
Vol 4 (4) ◽  
pp. 7290.2005.05133 ◽  
Author(s):  
Matthew J. Hardwick ◽  
Ming-Kai Chen ◽  
Kwamena Baidoo ◽  
Martin G. Pomper ◽  
Tomás R. Guilarte
Keyword(s):  
In Vivo Imaging ◽  
Ex Vivo ◽  
Inflammatory Diseases ◽  
Imaging Techniques ◽  
Benzodiazepine Receptors ◽  
Small Animal ◽  
Small Animal Pet ◽  
Planar Imaging ◽  
Peripheral Benzodiazepine Receptors

The ability to visualize the immune response with radioligands targeted to immune cells will enhance our understanding of cellular responses in inflammatory diseases. Peripheral benzodiazepine receptors (PBR) are present in monocytes and neutrophils as well as in lung tissue. We used lipopolysaccharide (LPS) as a model of inflammation to assess whether the PBR could be used as a noninvasive marker of inflammation in the lungs. Planar imaging of mice administrated 10 or 30 mg/kg LPS showed increased [123I]-( R)-PK11195 radioactivity in the thorax 2 days after LPS treatment relative to control. Following imaging, lungs from control and LPS-treated mice were harvested for ex vivo gamma counting and showed significantly increased radioactivity above control levels. The specificity of the PBR response was determined using a blocking dose of nonradioactive PK11195 given 30 min prior to radiotracer injection. Static planar images of the thorax of nonradioactive PK11195 pretreated animals showed a significantly lower level of radiotracer accumulation in control and in LPS-treated animals ( p < .05). These data show that LPS induces specific increases in PBR ligand binding in the lungs. We also used in vivo small-animal PET studies to demonstrate increased [11C]-( R)-PK11195 accumulation in the lungs of LPS-treated mice. This study suggests that measuring PBR expression using in vivo imaging techniques may be a useful biomarker to image lung inflammation.

SPECT Quantification of [123I]Iomazenil Binding to Benzodiazepine Receptors in Nonhuman Primates: II. Equilibrium Analysis of Constant Infusion Experiments and Correlation with in vitro Parameters

1994 ◽  
Vol 14 (3) ◽  
pp. 453-465 ◽  
Author(s):  
Marc Laruelle ◽  
Anissa Abi-Dargham ◽  
Mohammed S. AI-Tikriti ◽  
Ronald M. Baldwin ◽  
Yolanda Zea-Ponce ◽  
...  
Keyword(s):  
Specific Activity ◽  
Single Photon ◽  
Benzodiazepine Receptors ◽  
Photon Emission ◽  
Benzodiazepine Receptor ◽  
Equilibrium Analysis ◽  
Constant Infusion ◽  
Scatchard Analysis

In vivo benzodiazepine receptor equilibrium dissociation constant, KD, and maximum number of binding sites, Bmax, were measured by single photon emission computerized tomography (SPECT) in three baboons. Animals were injected with a bolus followed by a constant i.v. infusion of the high affinity benzodiazepine ligand [123I]iomazenil. Plasma steady-state concentration and receptor–ligand equilibrium were reached within 2 and 3 h, respectively, and were sustained for the duration (4–9 h) of the experiments (n = 15). At the end of the experiments, a receptor saturating dose of flumazenil (0.2 mg/kg) was injected to measure nondisplaceable activity. Experiments were carried out at various levels of specific activity, and Scatchard analysis was performed for derivation of the KD (0.59 ± 0.09 n M) and Bmax (from 126 n M in the occipital region to 68 n M in the striatum). Two animals were killed and [125I]iomazenil Bmax and KD were measured at 22 and 37°C on occipital homogenate membranes. In vitro values of Bmax (114 ± 33 n M) and 37°C KD (0.66 ± 0.16 n M) were in good agreement with in vivo values measured by SPECT. This study demonstrates that SPECT can be used to quantify central neuroreceptors density and affinity.

scholarly journals Extracellular pyridine nucleotides trigger plant systemic immunity through a lectin receptor kinase/BAK1 complex

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Chenggang Wang ◽  
Xiaoen Huang ◽  
Qi Li ◽  
Yanping Zhang ◽  
Jian-Liang Li ◽  
...  
Keyword(s):  
Nicotinamide Adenine Dinucleotide ◽  
Systemic Acquired Resistance ◽  
Plant Immunity ◽  
Acquired Resistance ◽  
Receptor Complex ◽  
Pyridine Nucleotides ◽  
Receptor Kinase ◽  
Systemic Immunity ◽  
Lectin Receptor

Abstract Systemic acquired resistance (SAR) is a long-lasting broad-spectrum plant immunity induced by mobile signals produced in the local leaves where the initial infection occurs. Although multiple structurally unrelated signals have been proposed, the mechanisms responsible for perception of these signals in the systemic leaves are unknown. Here, we show that exogenously applied nicotinamide adenine dinucleotide (NAD+) moves systemically and induces systemic immunity. We demonstrate that the lectin receptor kinase (LecRK), LecRK-VI.2, is a potential receptor for extracellular NAD+ (eNAD+) and NAD+ phosphate (eNADP+) and plays a central role in biological induction of SAR. LecRK-VI.2 constitutively associates with BRASSINOSTEROID INSENSITIVE1-ASSOCIATED KINASE1 (BAK1) in vivo. Furthermore, BAK1 and its homolog BAK1-LIKE1 are required for eNAD(P)+ signaling and SAR, and the kinase activities of LecR-VI.2 and BAK1 are indispensable to their function in SAR. Our results indicate that eNAD+ is a putative mobile signal, which triggers SAR through its receptor complex LecRK-VI.2/BAK1 in Arabidopsis thaliana.

scholarly journals 3528 Common Mechanisms Underlying Epilepsy and Tauopathy

2019 ◽  
Vol 3 (s1) ◽  
pp. 6-6 ◽  
Author(s):  
Ryan Adam Cloyd ◽  
Joe Abisambra ◽  
Bret Smith
Keyword(s):  
Status Epilepticus ◽  
Tau Phosphorylation ◽  
Common Disease ◽  
Neurologic Disorders ◽  
Study Population ◽  
Future Work ◽  
Society Today ◽  
Significant Health ◽  
Time Point

OBJECTIVES/SPECIFIC AIMS: Neurologic disorders are among the most significant health challenges facing society today. Although different neurologic disorders are often thought to be distinct from one another, evidence suggests similar processes may contribute to pathology in different diseases. Previous studies suggest that common disease mechanisms contribute to the development of epilepsy and tauopathy. The purpose of this study is to better characterize this relationship and explore potential therapeutic avenues to slow disease progress. METHODS/STUDY POPULATION: This study uses the pilocarpine-induced status epilepticus model of temporal lobe epilepsy to explore the effect of severe seizures on tau pathology. Brains were collected from mice at 6 or 24 hours after induced status epilepticus. Homogenates were analyzed via Western blot to look for changes in tau phosphorylation or activity of two major regulators of tau phosphorylation, GSK3β and PP2A. These data show that changes in tau phosphorylation dynamics occur at a much earlier time point after status epilepticus than has previously been described. RESULTS/ANTICIPATED RESULTS: GSK3β activity increased within 6 hours and remained elevated by 24 hours. PP2A activity initially decreased but returned to normal by 24 hours. These data show that changes in tau phosphorylation dynamics occur at a much earlier time point after status epilepticus than has previously been described. DISCUSSION/SIGNIFICANCE OF IMPACT: The current project supports previous observations that seizures promote tau phosphorylation in vivo, but suggests that changes begin much earlier than previously thought. Further work is needed to understand how post-seizure changes in tau phosphorylation develop over longer periods of time. Additionally, future work will characterize the effect of tauopathy on electrical activity in vivo and in vivo.

Sign in / Sign up

Export Citation Format

Share Document