| 1. |
- Bergquist, Jonas, et al.
(författare)
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Capillary electrophoresis with laser-induced fluorescence detection : a sensitive method for monitoring extracellular concentrations of amino acids in the periaqueductal grey matter.
- 1996
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Ingår i: Journal of Neuroscience Methods. - : Elsevier BV. - 0165-0270 .- 1872-678X. ; 65:1, s. 33-42
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Tidskriftsartikel (refereegranskat)abstract
- The use of capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) for the analysis of microdialysate samples from the periaqueductal grey matter (PAG) of freely moving rats is described. By employing 3-(4-carboxybenzoyl)-2-quinoline-carboxaldehyde (CBQCA) as a derivatization agent, we simultaneously monitored the concentrations of 8 amino acids (arginine, glutamine, valine, gamma-amino-n-butyric acid (GABA), alanine, glycine, glutamate, and aspartate), with nanomolar and subnanomolar detection limits. Two of the amino acids (GABA and glutamate) were analysed in parallel by conventional high-performance liquid chromatography (HPLC) in order to directly compare the two analytical methods. Other CE methods for analysis of microdialysate have been previously described, and this improved method offers greater sensitivity, ease of use, and the possibility to monitor several amino acids simultaneously. By using this technique together with an optimised form of microdialysis technique, the tiny sample consumption and the improved detection limits permit the detection of fast and transient transmitter changes.
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| 2. |
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| 3. |
- Bergquist, Jonas, et al.
(författare)
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Measurements of catecholamine-mediated apoptosis of immunocompetent cells by capillary electrophoresis.
- 1997
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Ingår i: Electrophoresis. - : Wiley. - 0173-0835 .- 1522-2683. ; 18:10, s. 1760-6
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Tidskriftsartikel (refereegranskat)abstract
- Single cell analysis with capillary electrophoresis, a technique capable of detecting zeptomole quantities (10(-21) mole) of neurochemical species, has been used to demonstrate that lymphocytes are capable of active synthesis of dopamine and norepinephrine. Exposure of lymphocytes to catecholamines at concentrations as low as 10 nM leads to decreased proliferation and differentiation, e.g. interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and immunoglobulin (Ig). In addition, both inhibition of dopamine uptake with nomifensine and inhibition of packing of catecholamines into vesicles with tetrabenazine, results in significantly lower levels of dopamine and norepinephrine (p < 0.01 and p < 0.05, respectively). The catecholamine-dependent inhibition of T- and B-lymphocyte activity is mediated via an induction of a Bcl-2/Bax and Fas/FasL involved apoptosis. These findings indicate a novel mechanism for regulation of lymphocyte activity in the central nervous system, whereby elevated regional levels of catecholamines might lead to the immunoprivilege of the brain.
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| 4. |
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| 5. |
- Blomqvist, M, et al.
(författare)
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Identification of defensins in human lymphocyte nuclei
- 1999
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Ingår i: European Journal of Biochemistry. - : Wiley. - 0014-2956 .- 1432-1033. ; 263:2, s. 312-8
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Tidskriftsartikel (refereegranskat)abstract
- The cell nucleus plays an essential role in all aspects of cell function and regulation. Most of the nuclear proteins/peptides are synthesized in the cytoplasm and transported into the nucleus through the nuclear pore complexes. The nuclear proteins/peptides conjugate with each other and interact in transcriptional activation/inactivation. Several of the high molecular mass transcription factors (> 30 kDa) have been identified and characterized. However, the information on the low molecular mass proteins/peptides of the nucleus is limited. We have investigated these low molecular mass proteins/peptides from the nucleus of human peripheral blood lymphocytes using reversed-phase high-performance liquid chromatography (RP-HPLC). The HPLC fractions were further analysed by matrix assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry, electrospray ionization time of flight (ESI-TOF) mass spectrometry and electrospray ionization fourier transform ion cyclotron resonance (ESI-FTICR) mass spectrometry for mass determination. Using this combination of mass spectrometry techniques and microsequence analysis, we have shown that human lymphocyte nuclei contain defensins, a mixture of human neutrophil granule peptide 1, 2 and 3.
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| 6. |
- Davidsson, P, et al.
(författare)
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Synaptotagmin, a synaptic vesicle protein, is present in human cerebrospinal fluid : a new biochemical marker for synaptic pathology in Alzheimer disease?
- 1996
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Ingår i: Molecular and chemical neuropathology. - 1044-7393 .- 2168-8729. ; 27:2, s. 195-210
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Tidskriftsartikel (refereegranskat)abstract
- Using a novel approach, including affinity chromatography, reversed-phase chromatography, and chemiluminescence immunoblotting, we have for the first time been able to demonstrate one of the small synaptic vesicle proteins, synaptotagmin I, in cerebrospinal fluid (CSF). Two other small synaptic vesicle proteins, rab3a and synaptophysin, were not detectable. The approximate molecular weight of CSF-synaptotagmin was 65 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Further characterization of CSF synaptotagmin by high-performance capillary electrophoresis (HPCE) showed a single peak. These findings support that the whole synaptotagmin molecule is present in CSF, without significant proteolytic degradation. After high-speed centrifugation of CSF, synaptotagmin was exclusively found in the supernatant, suggesting that synaptotagmin is present in CSF as a free protein, and not as a constituent of synaptic vesicles. In a preliminary study, we found a marked reduction of CSF synaptotagmin in patients with early onset Alzheimer disease (EAD) as compared with age-matched healthy individuals. To elucidate the biological relevance of this finding, we also quantified synaptotagmin in brain tissue. A marked reduction in synaptotagmin was found both in the hippocampus and frontal cortex of EAD, suggesting that a decrease in synaptotagmin in the brain is followed by a concomitant decrease in the CSF. Analysis of CSF synaptotagmin might provide a tool to study synaptic function and pathology in the human brain.
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| 7. |
- Josefsson, E, et al.
(författare)
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Catecholamines are synthesized by mouse lymphocytes and regulate function of these cells by induction of apoptosis.
- 1996
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Ingår i: Immunology. - 0019-2805 .- 1365-2567. ; 88:1, s. 140-6
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Tidskriftsartikel (refereegranskat)abstract
- The immune and the nervous systems are anatomically closely related and interact with each other by molecules common to both systems, such as cytokines and neurotransmitters. The purpose of this study was to investigate the participation of catecholamines in the neuroimmunological network. The ability of immune cells to produce catecholamines was examined by a highly sensitive capillary electrophoresis assay, which permits detection of easily oxidized catecholamines in the zeptomole (10(-21)) range. In addition, the effects of catecholamines on in vitro proliferation, differentiation and apoptosis of lymphocytes were assessed. Mouse spleen cells and macrophages contained on average 7 x 10(-17) and 2 x 10(-17) mole dopamine per cell, respectively. In the former cell population also norepinephrine was found. Several mouse B- and T-cell hybridomas were also shown to contain endogenously produced dopamine in levels ranging from 7 x 10(-20) to 2 x 10(-18) mole dopamine per cell. In addition, one of the T-cell hybridomas proved to synthesize norepinephrine. The dopamine production of lymphocytes was blocked by the tyrosine hydroxylase inhibitor alpha-methyl-p-tyrosine, whereas incubation with the precursor L-DOPA increased the dopamine content. Incubation with L-DOPA, dopamine and norepinephrine dose-dependently suppressed mitogen induced proliferation and differentiation of mouse lymphocytes. Even short-time pretreatment of lymphocytes with L-DOPA and dopamine strongly suppressed lymphocyte proliferation and cytokine production. Incubation of lymphoid cells with L-DOPA, dopamine and norepinephrine dose-dependently induced apoptosis which, at least partly, explains the suppressive effects of catecholamines on lymphocyte function. Our results demonstrate that catecholamines: (i) are actively produced by lymphocytes and (ii) have the capacity to act as auto- and/or paracrine regulators of lymphocyte activity through induction of apoptosis.
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| 8. |
- Stiller, C O, et al.
(författare)
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Local administration of morphine decreases the extracellular level of GABA in the periaqueductal gray matter of freely moving rats.
- 1996
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 209:3, s. 165-8
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Tidskriftsartikel (refereegranskat)abstract
- Opioids are generally believed to activate descending pain inhibitory pathways from the periaqueductal gray matter (PAG). Since opioids exert an inhibitory effect on neural excitability and transmitter release, an opioid-mediated inhibition of tonically active inhibitory gamma-aminobutyric acid (GABA) neurons has been suggested to mediate this effect. The aim of the present microdialysis study was to investigate the effect of local administration of morphine on the extracellular GABA level in the PAG of awake rats. The recently developed and highly sensitive method of capillary electrophoresis with laser-induced fluorescence detection was used for GABA determination in microdialysate samples obtained from the PAG of freely moving rats. The basal GABA level was 54.5 +/- 6.6 nM (n = 8; mean +/- SEM). Perfusion of the dialysis probe with morphine (100 microM) for 30 min significantly decreased the GABA level to 28.2 +/- 4.2 nM (n = 8; P < 0.05). The effect of morphine was reversed by coperfusion with naloxone (100 microM in the perfusion fluid). The present results thus provide direct experimental evidence for an opioid-induced inhibition of tonic GABA release in the PAG, which may in turn lead to a disinhibition of descending pain inhibitory pathways.
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