Search results for "Inhibition"
showing 10 items of 590 documents
Disruption of Slc4a10 augments neuronal excitability and modulates synaptic short-term plasticity
2015
Slc4a10 is a Na(+)-coupled Cl(-)-HCO3 (-) exchanger, which is expressed in principal and inhibitory neurons as well as in choroid plexus epithelial cells of the brain. Slc4a10 knockout (KO) mice have collapsed brain ventricles and display an increased seizure threshold, while heterozygous deletions in man have been associated with idiopathic epilepsy and other neurological symptoms. To further characterize the role of Slc4a10 for network excitability, we compared input-output relations as well as short and long term changes of evoked field potentials in Slc4a10 KO and wildtype (WT) mice. While responses of CA1 pyramidal neurons to stimulation of Schaffer collaterals were increased in Slc4a1…
Mechanism underlying the inhibitory sidebands in the receptive field of simple striate cells of the cat: pure on/off antagonism only or true inhibiti…
1985
The intrinsic organization of the receptive fields of simple striate cells revealed by moving stimuli is much more complex than could have been suspected from the use of stationary ones. There is, in fact, a small excitatory region centrally located in these receptive fields and an inhibitory region encompassing the whole excitatory component. These inhibitory regions or “inhibitory sidebands”, were identified by stimulating the cells with bars of light against anartificial background discharge produced by repeated asynchronous stimulation of the excitatory component of the cell's receptive field. For a long time' these inhibitory sidebands have been accounted for on the basis of the recept…
Study on the transient characteristic in the human visual system using masking experiments
1979
In this paper the visual masking effect is interpreted on the basic of the transient characteristic in two dimensional neuronal networks. The study investigates the suitability of the effect for use as a measurement method. It is shown that the stimulus distribution in space can be scanned at different points in time and that various dynamic characteristic values of the system can be measured.
Neuronal network characteristics in the cat superior colliculus
1977
The system theoretical description of the superficial layers of neurons in the cat's superior colliculus is based on homogeneous linear space-time filters. The most important neurophysiological findings on the superior colliculus are simulated on the digital computer by generating suitable coupling functions and matching the space and time parameters. It is shown that the neurophysiological measurements can be interpreted by varying a few system parameters. The curves of velocity dependent responses, direction specificity and the effects of the colliculus specific surround are examined in particular. Computer simulation shows that such a surround can evaluate small moving stimuli differentl…
Coupling of electrochemical, electrogravimetric and surface analysis techniques to study dithiocarbamate/bronze interactions in chloride media
2018
International audience; Interaction between ammonium pyrrolidinedithiocarbamate (PDTC) and bronze in 30 g L-1 NaCl was investigated at several concentrations between 0.1 and 10 mM by means of various electrochemical and spectroscopic techniques. Electrochemical measurements revealed a fast adsorption process of PDTC on Cu and Pb and the formation of a thick insulating and protective film with a high surface coverage. At high concentrations, PDTC prevents oxides formation. Surface analyses confirm PDTC adsorption on bronze mainly via interaction between sulphur atoms and Cu sites to form Cu I-PDTC complex.
ChemInform Abstract: Synthesis and Antineoplastic Activity of New 4-Diazopyrazole Derivatives.
2010
Several new 4-diazopyrazole derivatives were synthesized by reaction of 1-(R-substituted)phenyl-3-methyl-5-benzamidopyrazoles with a sevenfold excess of nitrous acid in acetic media. The compounds were tested at 20 microM concentration for their antineoplastic activity in vitro against Raji (human Burkitt lymphoma), K562 (human chronic myelogenous leukemia) and U937 (human histiocytic lymphoma) cell lines. They showed a percent of growth inhibition in the range 23.4-100%.
Phytosterols: to be or not to be toxic; that is the question
2008
Plant sterols (phytosterols) are membrane constituents of all plants with a structure analogous to that of cholesterol. Thus, phytosterols have either an additional methyl or ethyl group on the carbon-24 position or an additional double bond in the side chain (1) . Noteworthy, in patients with the rare inherited disease of phytosterolaemia characterized by a hyperabsorption and diminished biliary secretion of cholesterol and phytosterols as well as by tendon and tuberous xanthoma, elevated plasma concentrations of phytosterols (campesterol, sitosterol) have been shown to constitute a risk factor for premature atherosclerosis (2) . However, whether plasma concentrations of campesterol and si…
Characterization of somatostatin- and cholecystokinin-immunoreactive periglomerular cells in the rat olfactory bulb.
2005
Periglomerular cells (PG) are interneurons of the olfactory bulb (OB) that modulate the first synaptic relay of the olfactory information from the olfactory nerve to the dendrites of the bulbar principal cells. Previous investigations have pointed to the heterogeneity of these interneurons and have demonstrated the presence of two different types of PG. In the rat OB, type 1 PG receive synaptic contacts from the olfactory axons and are γ-aminobutyric acid (GABA)-ergic, whereas type 2 PG do not receive synaptic contacts from the olfactory axons and are GABA immunonegative. In this study, we analyze and characterize neurochemically a group of PG that has not been previously classified either …
Nitric oxide synthase containing periglomerular cells are GABAergic in the rat olfactory bulb.
2003
In the olfactory glomeruli of the rat olfactory bulb, there is a population of periglomerular cells (PG) that contains the neuronal isoform of the nitric oxide synthase (nNOS). To date, these PG have not been characterized neurochemically and it has not been determined whether they are type 1 (GABAergic PG that receive synaptic contacts from the olfactory axons) or type 2 PG (non-GABAergic PG that do not receive synapses from the olfactory axons). Combining pre-embedding NADPH-diaphorase histochemistry and post-embedding immunoperoxidase detection of GABA, we demonstrate that nNOS-containing PG are GABAergic and therefore, belong to the type 1 PG. The possible actions of nitric oxide in the…
Mechanisms of Raf-1 Kinase Inhibitor Protein Dysregulation in Triple-Negative Breast Cancers and Identification of Possible Novel Therapeutic Approac…
2014
Triple-negative breast cancers (TNBCs) are a heterogenous group of breast cancers characterized by poor prognosis because they are not amenable to targeted therapies. We have taken into account that altered expression of Raf-1 kinase inhibitor protein (RKIP), a tumor and metastasis suppressor and a promoter of drug-induced apoptosis, is frequent in TNBCs and may be involved in their aggressive biology. Interestingly, the analysis of the possible mechanisms of RKIP downregulation in TNBCs permits the identification and recapitulation of different possible approaches, including epigenetic modulation, e.g., by DNA demethylating agents or histone deacetylase inhibition, and NF-κB inhibition. Th…