Search results for "Postsynaptic potential"
showing 10 items of 371 documents
Intracellular Na+ concentration influences short-term plasticity of glutamate transporter-mediated currents in neocortical astrocytes.
2012
Fast synaptic transmission requires a rapid clearance of the released neurotransmitter from the extracellular space. Glial glutamate transporters (excitatory amino acid transporters, EAATs) strongly contribute to glutamate removal. In this work, we investigated the paired-pulse plasticity of synaptically activated, glutamate transporter-mediated currents (STCs) in cortical layer 2/3 astrocytes. STCs were elicited by local electrical stimulation in layer 4 in the presence of ionotropic glutamate (AMPA and NMDA), GABAA, and GABAB receptor antagonists. In experiments with low [Na+]i (5 mM) intrapipette solution, STCs elicited by paired-pulse stimulation demonstrated paired-pulse facilitation (…
B8, DR3 antigens and production of human leucocyte migration inhibitory factor (LIF) by mononuclear cells stimulated with concanavalin A (Con A)
2008
LIF release by Con A stimulated mononuclear cells was evaluated in 67 randomly selected healthy Sicilians typed for HLA antigens. The results show that B8 and/or DR3 positive subjects release less LIF than negative ones, suggesting that this immunological response might be controlled by HLA-linked immune response (Ir) gene(s).
Spontaneous lymphokine production by human B lymphocytes.
2009
When human blood lymphocytes are cultured in vitro without any intended stimulus, they produce activities in the supernatant resembling lymphokine. This phenomenon was further investigated in the present study, where it has been demonstrated by physicochemical characterization and inhibition experiments that leukocyte migration inhibitory activity in the supernatants is due to leukocyte inhibitory factor (LIF). When T and B lymphocytes were purified by carbonyl iron and SRBC-rosette sedimentation, only B cells produced LIF and leukocyte chemotactic lymphokine(s) in subsequent cultures. B cells elaborated lymphokines without the help of T cells, the need for co-operation of monocytes was als…
Modifications in Evoked Activity in the Visual Cortex Induced by the Caudate Nucleus
1971
The visual system, like the other sensorial systems, is subjected to intrinsic, complex control, originating both in the retina (CHANG et al., 1959; ARDUINI and HIRAO, 1960; STERIADE, 1967) and in the visual cortex (BUSER et a/., 1963; JASSIK-GERSCHENFELD and ASCHER, 1963; MEULDERS, 1965), which regulates its input at various levels of the specific pathways. However, the visual system is also influenced by subcortical structures which, though not exerting on it a strictly selective control, determine notable modifications in the level of excitability of the cortical sensorial neurons. It is in fact we11 known that activation of the mesencephalic reticular formation, by increasing the level …
Subventricular zone neural progenitors protect striatal neurons from glutamatergic excitotoxicity.
2012
The functional significance of adult neural stem and progenitor cells in hippocampal-dependent learning and memory has been well documented. Although adult neural stem and progenitor cells in the subventricular zone are known to migrate to, maintain and reorganize the olfactory bulb, it is less clear whether they are functionally required for other processes. Using a conditional transgenic mouse model, selective ablation of adult neural stem and progenitor cells in the subventricular zone induced a dramatic increase in morbidity and mortality of central nervous system disorders characterized by excitotoxicity-induced cell death accompanied by reactive inflammation, such as 4-aminopyridine-i…
The expression mechanism of the residual LTP in the CA1 region of BDNF k.o. mice is insensitive to NO synthase inhibition
2011
Abstract BDNF and nitric oxide signaling both contribute to long-term potentiation (LTP) at glutamatergic synapses, but to date, few studies analyzed the interaction of both signaling cascades in the same synaptic pathway. Here we addressed the question whether the residual LTP in the CA1 region of hippocampal slices from heterozygous BDNF knockout mice (BDNF +/− ) is dependent on nitric oxide (NO) signaling. Extracellular recording of synaptic field potentials elicited by presynaptic Schaffer collateral stimulation was performed in the CA1 region of hippocampal slices of 4- to 6-week-old mice, and LTP was induced by a theta burst stimulation protocol. Application of the nitric oxide inhibi…
Cannabinoid CB1 Receptor Calibrates Excitatory Synaptic Balance in the Mouse Hippocampus
2015
The endocannabinoid system negatively regulates the release of various neurotransmitters in an activity-dependent manner, thereby influencing the excitability of neuronal circuits. In the hippocampus, cannabinoid type 1 (CB1) receptor is present on both GABAergic and glutamatergic axon terminals. CB1 receptor-deficient mice were previously shown to have increased hippocampal long-term potentiation (LTP). In this study, we have investigated the consequences of cell-type-specific deletion of the CB1 receptor on the induction of hippocampal LTP and on CA1 pyramidal cell morphology. Deletion of CB1 receptor in GABAergic neurons in GABA-CB1-KO mice leads to a significantly decreased hippocampal …
Amino acid transport in the retina.
1978
The uptake, exit, homoexchange, inhibitory pattern, and kinetic analysis of transport of three amino acids were studied in the isolated retina of adult rat under different metabolic conditions. Only in the case of glycine, uptake and exit were shown to duplicate the processes observed in brain slices. In the case of lysine, glucose and oxygen showed an inhibitory effect, but with glutamate spontaneous exit could not be measured. It was also found that the rate of homoexchange for glycine and glutamate, but not for lysine, increases in the presence of oxygen and glucose.
Influence of Dimerization of Apocynin on Its Effects in Experimental Colitis
2017
Apocynin has been widely used as an inhibitor of the nicotinamide adenine dinucleotide phosphate oxidase (NADPH-oxidase) system and shows promise as an anti-inflammatory drug. Diapocynin, the dimeric product generated by the oxidation of apocynin in the presence of myeloperoxidase (MPO), is supposed to be its active form. In this study, diapocynin has been chemically synthesized and its activity on several inflammatory mediators in LPS-stimulated RAW 264.7 macrophages and its anti-inflammatory effect on ulcerative colitis induced by dextran sodium sulfate (DSS) in mice analyzed. We found that diapocynin showed higher inhibitory activity than apocynin. The dimer reduced ROS production, TNF-α…
Neurovascular EGFL7 regulates adult neurogenesis in the subventricular zone and thereby affects olfactory perception
2016
Adult neural stem cells reside in a specialized niche in the subventricular zone (SVZ). Throughout life they give rise to adult-born neurons in the olfactory bulb (OB), thus contributing to neural plasticity and pattern discrimination. Here, we show that the neurovascular protein EGFL7 is secreted by endothelial cells and neural stem cells (NSCs) of the SVZ to shape the vascular stem-cell niche. Loss of EGFL7 causes an accumulation of activated NSCs, which display enhanced activity and re-entry into the cell cycle. EGFL7 pushes activated NSCs towards quiescence and neuronal progeny towards differentiation. This is achieved by promoting Dll4-induced Notch signalling at the blood vessel-stem …