A5023550499- Connexins and lens biology
- Neuroscience and Neuropharmacology Research
- Ion channel regulation and function
- Immune Cell Function and Interaction
- Nicotinic Acetylcholine Receptors Study
- Photoreceptor and optogenetics research
- Fish biology, ecology, and behavior
- Neurobiology and Insect Physiology Research
- T-cell and B-cell Immunology
- Neural dynamics and brain function
- Neuroinflammation and Neurodegeneration Mechanisms
- Neuroscience and Neural Engineering
- Hematopoietic Stem Cell Transplantation
- Virus-based gene therapy research
- Immunotherapy and Immune Responses
- Ichthyology and Marine Biology
- Immune Response and Inflammation
- Physiological and biochemical adaptations
- Heat shock proteins research
- Neuroscience of respiration and sleep
- RNA regulation and disease
- Receptor Mechanisms and Signaling
- Mesenchymal stem cell research
- Lipid Membrane Structure and Behavior
- RNA Interference and Gene Delivery
Albert Einstein College of Medicine
2015-2024
The Francis Crick Institute
2023
Centro Hospitalar do Baixo Vouga
2019
Chinese Institute for Brain Research
2017
Fudan University
2016-2017
State Key Laboratory of Medical Neurobiology
2016-2017
John F. Kennedy Center for the Performing Arts
1973-2014
Yeshiva University
1992-2013
The University of Texas Southwestern Medical Center
1991-2006
Pontificia Universidad Católica de Chile
2001-2004
Calcium waves represent a widespread form of intercellular communication. Although they have been thought for long time to require gap junctions, we recently demonstrated that mouse cortical astrocytes use an extracellular messenger calcium wave propagation. The present experiments identify ATP as major in this system. Medium collected from astrocyte cultures during (but not before) stimulation contains ATP. excitatory effects medium samples and are blocked by purinergic receptor antagonists...
Hepatocytes are well coupled by gap junctions, which allow the diffusion of small molecules between cells. Although junctions in many tissues permeable to larger than cAMP and several preparations pass itself, little direct evidence supports permeation other second-messenger species. Ca2+, perhaps smallest second messenger, would be expected cross but issue is complicated because gap-junction channels closed when intracellular free Ca2+ concentration, [Ca2+]i, elevated micromolar levels or...
By using antibodies directed against gap junction proteins of liver (connexins 26 and 32) heart (connexin 43), we have localized immunoreactivity to specific cell types in frozen sections adult rodent brains. Connexin 32 reactivity was found oligodendrocytes also a few neurons, whereas connexins 43 leptomeningeal cells, ependymal pineal gland. Immunoreactivity with connexin occurred astrocytes. Furthermore, during embryonic postnatal maturation brain tissues, were differentially expressed....
Rat cortical astrocytes in pure culture are functionally coupled to neighboring cells via connexin (Cx) 43 gap junctions under ordinary conditions. Small fluorescent molecules such as Lucifer yellow (LY) pass between cell interiors junctions, but do not enter the when externally applied. Subjecting rat and mouse "chemical ischemia" by inhibition of glycolytic oxidative metabolism induced permeabilization ethidium bromide before loss membrane integrity determined dextran uptake lactate...
The p H of the cytoplasm ( i ) measured with H-sensitive microelectrodes in cleavage-stage blastomeres amphibian Ambystoma and teleost Fundulus embryos is about 7.7. In electrotonically coupled cell pairs, junctional conductance rapidly reversibly reduced by acidification cytoplasm. relation between same for increasing decreasing independent rate change over a wide range. well fitted Hill curve K = 50 n M (p 7.3) 4 to 5. closure gap junction channels at low appears be cooperative process...
Connexin 43 (Cx43) nonjunctional or “unapposed” hemichannels can open under physiological pathological conditions. We characterize comprised of Cx43 Cx43-EGFP (Cx43 with enhanced GFP fused to the C terminus) expressed in HeLa cells. Channel opening was induced at potentials greater than +60 mV. Open probability appeared be very low. No comparable detected parental, nontransfected Conductance fully single ≈220 pS, which is approximately double that cell–cell channels. exhibited two types...
Severe, transient global ischemia of the brain induces delayed damage to specific neuronal populations. Sustained Ca2+ influx through glutamate receptor channels is thought play a critical role in postischemic cell death. Although most kainate-type receptors are Ca(2+)-impermeable, Ca(2+)-permeable kainate have been reported kinds neurons and glia. Recombinant assembled from GluR1 and/or GluR3 subunits exogenous expression systems permeable Ca2+; heteromeric containing GluR2...
The conductance of junctions between amphibian blastomeres is strongly voltage dependent. Isolated pairs from embryos Ambystoma mexicanum, Xenopus laevis, and Rana pipiens were clamped, junctional current was measured during transjunctional steps. steady-state decreases as a steep function either polarity. A voltage-insensitive less than 5% the maximum remains at large voltages. Equal voltages opposite polarities produce equal changes. half maximal approximately 15 mV. insensitive to...
Membrane-permeant cAMP derivatives (dibutyryl- and 8-bromo-cAMP) increase gap-junctional conductance within minutes when applied to voltage-clamped pairs of rat hepatocytes. Glucagon also increases junctional conductances, but the response has a more rapid onset is rapidly reversible. The glucagon effect can be prevented by intracellular injection protein inhibitor cAMP-dependent kinase (Walsh inhibitor), indicating that catalytic subunit directly involved. 27-kDa major gap junction...
Inflammation contributes to neurodegeneration in post-ischemic brain, diabetes, and Alzheimer's disease. Participants this inflammatory response include activation of microglia astrocytes. We studied the role treated with amyloid-β peptide (Aβ) on hemichannel activity astrocytes subjected hypoxia high glucose. Reoxygenation after 3 h glucose induced transient astroglial permeabilization via Cx43 hemichannels reduction intercellular communication cell-cell channels. Both responses were...
F1 hybrid mice are capable of rejecting inbred parental strain bone marrow grafts after a single lethal exposure to X-rays. The incompatibility is genetically controlled by the Hybrid-histocompatibility-1 (Hh-1) locus in or near D end Histocompatibility-2 (H-2) region. onset graft rejection begins 9–12 hr transplantation and completed 24 hr. Maturation resistance does not occur until 22nd day life. In adults, can be temporarily abrogated weakened administration cyclophosphamide dead cultures...
Mice are capable of rejecting H-2-incompatible bone marrow grafts after a single lethal exposure to X-rays. The onset rejection begins 18-24 hr transplantation and is completed by 96 hr. Maturation this type allograft reactivity does not occur until the 22nd day life. In adult mice, resistance allografts can be weakened administration cyclophosphamide or dead cultures Corynebacterium parvum, but heterologous anti-thymocyte serum. Sublethal exposures X-rays 7 14 days before also weaken...
Significance Moderate or severe traumatic brain injury (TBI) damages white matter, thereby contributing to long-term neurological deficits. Currently, there are no satisfactory therapies mitigate this matter (WMI). Here we show that inhibition of histone deacetylases (HDACs) exerts robust structural and functional protection in a murine model TBI/WMI by polarizing microglia/macrophages toward the beneficial M2 phenotype. HDAC shifted microglia/macrophage phenotype up-regulating glycogen...
The dye Procion Yellow M4RS crosses junctional membranes from cytoplasm to at electrotonic synapses between segments of the crayfish septate axon. does not enter cells extracellular space. Thus permeability is qualitatively different that nonjunctional membranes. Electron microscopy after fixation in presence lanthanum hydroxide indicates these are "gap junctions" and there a network channels continuous with space apposed These must be interlaced intercytoplasmic open