| 1. |
- Cardell, Monika, et al.
(författare)
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Protein kinase C is translocated to cell membranes during cerebral ischemia
- 1990
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940. ; 119:2, s. 228-232
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Tidskriftsartikel (refereegranskat)abstract
- The subcellular distribution of PKC(α) and PKC(γ) was studied in homogenates of cerebral cortex from rats subjected to 10 and 15 min of ischemia and 15 min of ischemia followed by 1 h, 6 h, 24 h, 48 h, and 7 days of reperfusion. During ischemia no significant changes in the levels of PKC (α) were seen. During the first hour of reperfusion, a transient 2.5-fold (P < 0.05) increase in PKC(α) levels was observed in the particulate fraction. In contrast, a three-fold increase of PKC(γ) in the particulate fraction concomitant with a 40% decrease in the cytosol was noted during ischemia. In the postischemic phase the levels in the cytosol decreased to 35% of control values at 2 days following ischemia, with a concomitant decrease in the particulate fraction to control levels. The redistribution of PKC to the cell membranes during and following ischemia could be due to ischemia induced receptor activation, increased levels of diacylglycerols, arachidonate and intracellular calcium, and may be of importance for the development of ischemic neuronal damage.
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| 2. |
- Edbladh, Magnus, et al.
(författare)
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Early regeneration in vitro of adult mouse sciatic axons is dependent on local protein synthesis but may not involve neurotrophins
- 1994
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940. ; 168:1-2, s. 37-40
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Tidskriftsartikel (refereegranskat)abstract
- The sensory axons of the adult mouse sciatic nerve were shown to regenerate after a local test crush lesion in vitro in a serum-free medium. The average outgrowth distance of the leading axons after culturing for 3 days was 2.8 ± 0.1 mm, which was shorter than in vivo (3.8 ± 0.2 mm). With the use of a compartmentalised culture system we could show that regeneration was partially dependent on local protein synthesis in the injury region. The initial stages of regeneration did not seem to involve neurotrophins since both K252a and K252b, selective and nontoxic inhibitors of the neurotrophin actions, failed to inhibit axonal growth. The present in vitro model system offers favourable conditions to investigate the early events of the regeneration process in an adult mammalian peripheral nerve.
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| 3. |
- Ekström, Per A R
(författare)
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Insulin stimulates ganglionic protein synthesis and reduces thymidine incorporation in support cells of the in vitro regenerating adult frog sciatic sensory neurons
- 1991
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940. ; 132:2, s. 183-186
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Tidskriftsartikel (refereegranskat)abstract
- Insulin was tested for effects on crush injured, in vitro regenerating, adult frog sciatic sensory axons. A wide range of insulin concentrations (0.01-10 μg × ml-1) was found to stimulate incorporation of radioactive leucine into ganglionic protein by 50-80%. without affecting the regeneration distance. Simultaneously insulin inhibited the proliferation of the support cells at the crush region by 30%, as measured by thymidine incorporation. Experiments using compartmentalized culture dishes indicated that the proliferation inhibitory effect could be indirect and mediated by the neuronal cells. The results suggest that insulin influences the metabolism of adult peripheral neuronal cell bodies. The stimulated nerve cells could in turn affect the proliferation of support cells in the nerve trunk.
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| 4. |
- Grundemar, L, et al.
(författare)
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Long-lasting inhibition of the cardiovascular responses to glutamate and the baroreceptor reflex elicited by neuropeptide Y injected into the nucleus tractus solitarius of the rat
- 1991
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940. ; 122:1, s. 135-139
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Tidskriftsartikel (refereegranskat)abstract
- Neuropeptide Y (NPY) microinjected unilaterally into the nucleus tractus solitarii (NTS) of anesthetized paralyzed rats elicits a gradual dose-dependent and reversible fall in arterial pressure (AP) and heart rate (HR) lasting 20 min. It also abolished the brief (less than 1 min) dose-dependent and reversible fall of AP and HR elicited by L-glutamate (L-Glu) injected into the nucleus. The blockade of L-Glu by NPY appeared gradually and was prolonged, lasting over 2 h, and recovering by 24 h. It was not replicated by desamido-NPY or galanin. Unlike 2% lidocaine it did not block the hypotension elicited by focal electrical stimulation at the injection site indicating the response was not that of a local anesthetic. Bilateral injection of NPY into the NTS resulted, after an initial fall, in an elevation of AP (+48 +/- 10.6 mmHg). At this time the reflex bradycardia evoked by elevating AP with phenylephrine was markedly reduced. We conclude that in the NTS, NPY antagonizes the actions of L-Glu and may attenuate baroreceptor reflexes. Since the NTS is richly innervated by NPY neurons and contains many NPY binding sites and since primary baroreceptor afferents appear to be glutamatergic the results suggested that NPY may serve in NTS as a long-term regulator of baroreceptor reflex activity.
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| 5. |
- Holmqvist, Bo I., et al.
(författare)
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Nitric oxide synthase in the brain of a teleost
- 1994
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940. ; 171:1-2, s. 205-208
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Tidskriftsartikel (refereegranskat)abstract
- The presence and distribution of the nitric oxide (NO) converting enzyme, NO synthase (NOS), was investigated in the brain of a teleost, the Atlantic salmon. Both NOS immunoreactive and NADPH diaphorase positive, non-neuronal and neuronal cell bodies, fibers and putative nerve terminals were identified throughout the brain. Even so, the staining was not identical in all regions. NO, synthesized by NOS-like enzymes, may play an important role in a diversity of cellular mechanisms in the brain of the salmon, including in neural systems related to olfactory, visual, hypophysiotrophic, viscero-sensoric and motor functions.
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| 6. |
- Larsson, Christer, et al.
(författare)
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Desensitization of acetylcholine induced inositol 1,4,5-trisphosphate formation in neuroblastoma SH-SY5Y cells following repetitive acetylcholine stimulations
- 1993
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Ingår i: Neuroscience Letters. - 0304-3940. ; 150:2, s. 141-144
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the desensitization of acetylcholine-induced inositol 1,4,5-trisphosphate [I(1,4,5)P3] formation, upon short-time prestimulations, was investigated in cultures of human neuroblastoma SH-SY5Y cells. Four repeated stimulations for 10 seconds with 10 microM acetylcholine were necessary to induce a desensitization of the I(1,4,5)P3 formation. The desensitization was observed 4 hours after the initiation of repetitive stimulations. The same effect was obtained by a single prestimulation with 1 mM acetylcholine. Preincubation of the cells with phorbol 12-myristate 13-acetate (PMA) markedly down-regulated the acetylcholine-induced I(1,4,5)P3 formation. However, the protein kinase C (PKC) inhibitors H7 and staurosporine did not influence the desensitization induced by four repeated stimulations with 20 microM acetylcholine. These results indicate that the signal transduction can be desensitized following repeated stimulations with sub-maximal concentrations of receptor agonist and although activation of PKC can induce the same down-regulation, PKC is most likely not involved in the desensitization induced by repetitive acetylcholine-stimulations.
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| 7. |
- Rutherford, Diane M, et al.
(författare)
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Isolation and identification from Salvia officinalis of two diterpenes which inhibit t-butylbicyclophosphoro[35S]thionate binding to chloride channel of rat cerebrocortical membranes in vitro
- 1992
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940. ; 135:2, s. 224-226
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Tidskriftsartikel (refereegranskat)abstract
- Ethanolic extracts from dried leaves of sage (Salvia officinalis) showed inhibition of [35S]tertiary-butylbicyclophosphorothionate ([35S]TBPS) binding to rat brain membranes in vitro. This ligand is considered to bind to the chloride channel of the GABA/benzodiazepine receptor complex in brain tissue. Substances having inhibitory activity were purified and their chemical structure identified as the diterpenes carnosic acid and carnosol (IC50 values of 33 +/- 3 microM and 57 +/- 4 microM, respectively). The two compounds did not affect binding of the ligands [3H]muscimol and [3H]diazepam to the GABA/benzodiazepine complex in vitro. Saturation experiments of [35S]TBPS binding indicated that carnosic acid decreases the binding affinity.
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| 8. |
- Vecino, E., et al.
(författare)
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Expression of the homeobox engrailed gene during the embryonic development of the nervous system of the trout (Salmo fario L.)
- 1991
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Ingår i: Neuroscience Letters. - 0304-3940. ; 129:2, s. 311-314
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Tidskriftsartikel (refereegranskat)abstract
- The expression of the engrailed homeobox gene during trout embryogenesis has been examined using immunohistochemistry and the monoclonal antibody 'Mab 4D9'. Engrailed has been suggested to play an important role during development by controlling position-specific characteristics in the CNS of the early embryo. In the present study we have analyzed the expression of engrailed at 5 stages of embryonic development of the trout (Salmo fario L.). The earliest stage analyzed was when the optic vesicles appear. Engrailed was then expressed in the posterior mesencephalon and anterior metencephalon, in a caudorostrally decreasing gradient. As the embryo develops, the pattern of the engrailed expression increases in spatial complexity. Thus, in the later stages of development, just before hatching, engrailed was found in hypothalamic areas, the germinative matrix layer of the cerebellum, the mesencephalic tegmentum, the caudal optic tectum and in the area of the trigeminal motor nucleus. This is similar to the distribution of engrailed in embryos of amphibians, birds and mammals.
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| 9. |
- Yáñez, Julián, et al.
(författare)
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Neural projections of the pineal organ in the larval sea lamprey (Petromyzon marinus L.) revealed by indocarbocyanine dye tracing
- 1993
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Ingår i: Neuroscience Letters. - 0304-3940. ; 164:1-2, s. 213-216
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of the central neural connections of the pineal organ of the larval sea lamprey was investigated by means of anterograde and retrograde tracing with the fluorescent lipophilic dye. DiI (1,1′-dioctadecyl 3,3,3′,3′-tetramethylindocarbocyanine perchlorate). Pinealofugal projections are well developed in larvae, extending from the posterior commissure into the diencephalon and mesencephalon. Small numbers of neurons were retrogradely labelled in the transition zone between the diencephalon and the mesencephalic tegmentum. These cells may consitute the first pinealopetal system described in anamniotes.
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| 10. |
- Giacobini, MaiBritt M J, et al.
(författare)
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Differential effects of platelet-derived growth factors on fetal hippocampal and cortical grafts : evidence from intraocular transplantation in rats
- 1992
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Ingår i: Neuroscience Letters. - 0304-3940 .- 1872-7972. ; 136:2, s. 227-231
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Tidskriftsartikel (refereegranskat)abstract
- Effects of platelet-derived growth factor-AA (PDGF-AA) and platelet-derived growth factor-BB (PDGF-BB) on developing parietal cortex (E16) and hippocampal (E18-E19) grafts were studied using the in vivo method of intraocular transplantation. Survival and growth of grafts in the anterior eye chamber of adult host rats under the influence of regular treatments with 0.5 ng (in a 100 ng/ml concentration) PDGF-AA or PDGF-BB was followed and compared to those receiving vehicle solution alone (0.5 mg HSA/ml Hanks). Both PDGF-AA and PDGF-BB increased the volume of transplanted cortical grafts. PDGF-BB also exerted trophic effects on grafted hippocampal tissue whereas PDGF-AA seemed to inhibit hippocampal growth. Histological and immunohistochemical studies revealed an increase in the density of astroglial elements in PDGF-AA- and PDGF-BB-treated cortical grafts whereas the PDGF-AA- and PDGF-BB-treated hippocampal grafts maintained a cytoarchitecture closely resembling that of control grafts. These findings support in vitro experiments showing that developing glial cells are stimulated by PDGFs and we further propose regional differences of action of PDGFs in the developing central nervous system.
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