| 1. |
- Boris-Möller, Fredrik, et al.
(författare)
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The effect of hypothermia on the expression of neurotrophin mRNA in the hippocampus following transient cerebral ischemia in the rat
- 1998
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Ingår i: Molecular Brain Research. - 0169-328X. ; 63:1, s. 163-173
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Tidskriftsartikel (refereegranskat)abstract
- The expression of the mRNAs of nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT3) and the neurotrophin receptor, TrkB, was studied in the rat hippocampus by in situ hybridization following normothermic (37°C) and protective hypothermic (33°C) transient cerebral ischemia of 15 min duration. In the resistant dentate gyms, normothermic ischemia transiently induced NGF mRNA at around 8 h of recovery, while the NT3 mRNA levels were depressed over at least a 24-h recovery period. The levels of BDNF and TrkB were transiently and markedly elevated with a maximal expression at 24 h of recovery. Intraischemic hypothermia reduced the induction of NGF mRNA, while the increase of BDNF mRNA expression occurred earlier during recovery, and the post-ischemic NT3 mRNA depression was not affected. Also, the expression of TrkB mRNA was enhanced, and occurred concomitantly with the elevation of BDNF mRNA. In contrast, there were no changes in neurotrophin and TrkB mRNA in the CA3 and CA1 regions. The expression of BDNF mRNA at 24 h after normothermic ischemia, was attenuated by intraischemic hypothermia. We conclude that, the expressions of NGF, BDNF, NT3 or TrkB mRNA in ischemia-sensitive hippocampal subregions are not increased by protective hypothermia. In contrast, hypothermia induces neurotrophin mRNA alterations in the ischemia-resistant dentate gyms that may convey protection to sensitive regions.
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| 2. |
- Ding, W Q, et al.
(författare)
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Effects of ethanol on muscarinic receptor-stimulated c-fos expression in human neuroblastoma cells
- 1997
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Ingår i: Brain Research. Molecular Brain Research. - 0169-328X. ; 46:1-2, s. 77-84
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Tidskriftsartikel (refereegranskat)abstract
- The effect of ethanol exposure on muscarinic receptor-stimulated expression of c-fos was investigated in SH-SY5Y cells. Four days of ethanol exposure enhanced carbachol-stimulated c-fos mRNA expression, analyzed with Northern blot, and Fos/AP-1 binding activity, measured with gel mobility super shift assay. Pre-incubation with muscarinic antagonists or the protein kinase C inhibitor GF109203X demonstrated that, in both control and ethanol-treated cells, carbachol-induced c-fos expression was mediated via muscarinic M1 receptors and to a large extent through protein kinase C. However, phorbol ester-induced c-fos expression was unaffected in ethanol-treated cells. Acute exposure to ethanol caused a suppression of both carbachol- and phorbol ester-stimulated c-fos expression. These results demonstrate that muscarinic receptor-stimulated gene expression is sensitive to both acute and long-term ethanol exposure.
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| 3. |
- IzquierdoClaros, R.M., et al.
(författare)
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Acute effects of D-1 and D-2-receptor agonist and antagonist drugs on somatostatin binding, inhibition of adenylyl cyclase activity and accumulation of inositol 1,4,5-trisphosphate in the rat striatum
- 1997
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Ingår i: Brain Research. Molecular Brain Research. - 0169-328X. ; 47:1-2, s. 99-107
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Tidskriftsartikel (refereegranskat)abstract
- A recent study carried out by our group demonstrated that exogenous dopamine increases the somatostatin (SS) receptor–effector system in the rat striatum. The present study examined the participation of the D1- and D2-dopaminergic systems in the modulation of the rat striatal SS receptor–effector system by use of the D1-receptor agonist and antagonist SKF 38393 and SCH 23390, respectively, and the D2-receptor agonist and antagonist bromocriptine and raclopride, respectively. In view of the rapid onset of dopamine action, the effect of dopaminergic agents on the SS mechanism of action were studied 3 h after their administration. SKF 38393 (4 mg/kg i.p.) or bromocriptine (2 mg/kg i.p.) administered to male Wistar rats increased the number of 125I-Tyr3-SMS receptors in the striatum (52 and 30%, respectively) without changing the affinity constant. The effect of SKF 38393 on 125I-Tyr3-SMS binding was antagonized by the D1-specific antagonist SCH 23390 (0.25 mg/kg i.p.) whereas the effect of bromocriptine was abolished by the D2-specific antagonist raclopride (5 mg/kg i.p.). No change in binding was produced when SKF 38393 or bromocriptine were added directly to the incubation medium. The acute systemic administration of SCH 23390 or raclopride alone had no effect on the binding of 125I-Tyr3-SMS to its receptors. The increase of the number of 125I-Tyr3-SMS receptor induced by SKF 38393 or bromocriptine was accompanied by an increase in the capacity of SMS 201-995 to inhibit basal and forskolin (FK)-stimulated adenylyl cyclase (AC) activity when compared to the control groups. In addition, the effect of SMS 201-995 on the mass accumulation of inositol 1,4,5-trisphosphate (IP3) was investigated. SKF 38393 as well as bromocriptine increased the capacity of SMS 201-995 to accumulate IP3 in the rat striatum although this effect was only statistically significant in the case of SKF 38393. These results suggest that the activation of D1 and D2 receptors increases the activity of the SS receptor–effector system, the effect being greater in the case of D1 receptors. These findings are consistent with a functional interaction between dopamine and SS in the rat striatum.
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| 4. |
- Kamme, Fredrik, et al.
(författare)
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Induction of junD mRNA after transient forebrain ischemia in the rat. Effect of hypothermia
- 1996
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Ingår i: Molecular Brain Research. - 0169-328X. ; 43:1-2, s. 51-56
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Tidskriftsartikel (refereegranskat)abstract
- The expression of junD was studied in the rat hippocampus by in situ hybridization after 15 min of normothermic (37°C) and hypothermic (33°C) transient forebrain ischemia. Ischemia was induced by common carotid artery occlusion combined with hypotension leading to damage in the CA1 region of the hippocampus which was prevented by hypothermia junD mRNA was induced in the hippocampus within 2 h of reperfusion and was strong in the dentate gyrus but weak in the CA3 acid CA1 subregions. Intraischemic hypothermia significantly augmented the junD induction in the dentate gyrus. During late reperfusion (between 12 and 36 h after ischemia) a transient increase in junD mRNA was seen in the normothernic CA3 which was abolished in the hypothermic brains. In contrast, in the normothermic CA1 a continuous increase of junD was seen. This was significantly reduced by intraischemic hypothermia. We suggest that the early induction in junD expression in the dentate gyrus and in the hypothermic CA3 region is a protective reaction to the ischemic stress. The marked increase in resistant brain areas could be due to the preserved intracellular signaling pathways and a subsequent maintenance of protein synthesis. The late continuous increase, unique to the vulnerable normothermic CA1 region, suggests that junD participates in a transcriptional process that may be important for delayed neuronal death in the hippocampus following transient forebrain ischemia.
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| 5. |
- Kokaia, Merab, et al.
(författare)
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Biphasic differential changes of GABAA receptor subunit mRNA levels in dentate gyrus granule cells following recurrent kindling-induced seizures
- 1994
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Ingår i: Brain Research. Molecular Brain Research. - 0169-328X. ; 23:4, s. 323-332
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Tidskriftsartikel (refereegranskat)abstract
- GABAA receptor alpha 1, beta 3 and gamma 2 subunit mRNA levels have been measured in hippocampus using in situ hybridization, following 1, 10 and 40 seizures produced by rapid kindling stimulations. Major alterations of gene expression were largely confined to the dentate gyrus. One stimulus-induced seizure reduced gamma 2 mRNA levels in the dentate gyrus by 30%. In contrast, mRNA expression increased for alpha 1 in CA1 and CA3 and for beta 3 in CA1 to around 30% above control values. Ten stimulations reduced beta 3 (by 19%) and gamma 2 (by 37%) mRNA expression in the dentate gyrus. No changes were observed in other hippocampal subregions. Forty kindling-induced seizures led to biphasic alterations of subunit mRNA levels in dentate gyrus with only minor changes in CA1-CA3. Up to 4 h after the last seizure mRNA expression for alpha 1 was slightly decreased in dentate gyrus, whereas marked reductions were observed for beta 3 and gamma 2 (by 41% and 48%, respectively). Between 12 and 48 h there were major increases of alpha 1 (by 59%) and gamma 2 (by 35%) mRNA levels but no significant changes of beta 3 mRNA expression. Subunit mRNA levels had returned to control values after 5 days, which argues against a direct involvement of GABAA receptor in kindling-evoked hyperexcitability. The rapid and transient, biphasic changes of GABAA receptor subunits following recurrent seizures could play an important role in stabilizing granule cell excitability, thereby reducing seizure susceptibility. The differential regulation of subunit mRNA levels following seizures suggests a novel mechanism for changing the physiological properties of dentate granule cells through possible GABAA receptor complexes with different subunit composition.
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| 6. |
- Kokaia, Zaal, et al.
(författare)
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Regional brain-derived neurotrophic factor mRNA and protein levels following transient forebrain ischemia in the rat
- 1996
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Ingår i: Brain Research. Molecular Brain Research. - 0169-328X. ; 38:1, s. 139-144
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Tidskriftsartikel (refereegranskat)abstract
- Levels of BDNF mRNA and protein were measured in the rat brain using in situ hybridization and a two-site enzyme immunoassay. Under basal conditions, the highest BDNF concentration was found in the dentate gyrus (88 ng/g), while the levels in CA3 (50 ng/g), CA1 (18 ng/g) and parietal cortex (8 ng/g) were markedly lower. Following 10 min of forebrain ischemia, BDNF protein increased transiently in the dentate gyrus (to 124% of control at 6 h after the insult) and CA3 region (to 131% of control, at 1 week after the insult). In CA1 and parietal cortex, BDNF protein decreased to 73-75% of control at 24 h. In contrast, BDNF mRNA expression in dentate granule cells and CA3 pyramidal layer was transiently elevated to 287 and 293% of control, respectively, at 2 h, whereas no change was detected in CA1 or neocortex. The regional BDNF protein levels shown here correlate at least partly with regional differences in cellular resistance to ischemic damage, which is consistent with the hypothesis of a neuroprotective role of BDNF.
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| 7. |
- Tomasevic, Gregor, et al.
(författare)
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Activation of p53 and its target genes p21(WAF1/Cip1) and PAG608/Wig-1 in ischemic preconditioning
- 1999
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Ingår i: Molecular Brain Research. - 0169-328X. ; 70:2, s. 304-313
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Tidskriftsartikel (refereegranskat)abstract
- A brief, 3 min period of global forebrain ischemia in the rat, induced by bilateral common carotid occlusion combined with hypotension, confers resistance to hippocampal pyramidal neurons against a subsequent 10 min ischemia, which is normally lethal to these cells. The molecular mechanisms underlying this ischemic preconditioning, or tolerance, are poorly understood. The tumor suppressor p53 is a transcription factor implicated in neuronal death following various insults, including cerebral ischemia. p53 is activated in response to cellular stress, e.g. hypoxia and DNA damage. Using in situ hybridization, we investigated the hippocampal mRNA expression of p53, and two of its target genes, p21(WAF1/Cip1) and the recently cloned PAG608/Wig-1, in a two-vessel occlusion model of ischemic preconditioning. We also evaluated changes in the protein levels of p53 and PAG608/Wig-1 using immunohistochemistry. The mRNA levels of all three genes increased in the ischemia sensitive CA1 region both following 3 min (non-lethal) preconditioning and 10 min of (lethal) nonconditioned ischemia. In contrast, after 10 min of ischemia preconditioned by a 3 min ischemic insult 48 h earlier, no upregulation of these genes was detected in the CA1. Following 10 min of nonconditioned ischemia, increased neuronal immunostaining of p53 and PAG608/Wig-1 was observed in the hippocampus, which was less pronounced following 3 min of preconditioning ischemia and 10 min of preconditioned ischemia. Our results demonstrate that activation of p53 and its response genes p21(WAF1/Cip1) and PAG608/Wig-1 occurs in the brain following lethal as well as non-lethal ischemic insults, and that ischemic preconditioning markedly diminishes this activation. Copyright (C) 1999 Elsevier Science B.V.
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| 8. |
- Tomasevic, Gregor, et al.
(författare)
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Changes in proliferating cell nuclear antigen, a protein involved in DNA repair, in vulnerable hippocampal neurons following global cerebral ischemia
- 1998
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Ingår i: Molecular Brain Research. - 0169-328X. ; 60:2, s. 168-176
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Tidskriftsartikel (refereegranskat)abstract
- Proliferating cell nuclear antigen (PCNA) is required for completion of the DNA synthesis step of DNA replication as well as nucleotide excision repair (NER) of damaged DNA. We investigated the expression of PCNA mRNA and the levels of PCNA protein in the adult rat hippocampus following normo- and hypothermic global forebrain ischemia. Hypothermia protected the CA1 neurons from ischemic damage. A constitutive expression of PCNA mRNA and protein was detected in all hippocampal subfields, as well as in other brain regions. During reperfusion, PCNA mRNA levels were up-regulated in the vulnerable CA1 subfield at 36 h following normothermic ischemia. In hypothermia, this induction appeared already after 18 h. Following normothermic ischemia, nuclear PCNA immunoreactivity was largely abolished during reperfusion in the vulnerable CA1 neurons, prior to cell death. In contrast, total PCNA protein content of this region, as measured by Western blotting, remained largely unchanged. In the CA3 region, a transient decrease in nuclear PCNA immunoreactivity was observed. In the dentate gyrus region, no down-regulation of nuclear or total PCNA protein was observed during reperfusion. Following hypothermic ischemia, the PCNA protein levels did not decrease in any of the hippocampal subregions. In contrast, no change in the levels of Ref-1, a protein involved in base excision DNA repair (BER), was observed following normo- or hypothermic ischemia. Our findings indicate an altered functional state of PCNA protein in the ischemia-sensitive CA1 neurons suggesting that DNA repair processes are affected in these post-mitotic cells following ischemia. Impaired DNA repair may play a role in the development of postischemic neuronal damage.
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| 9. |
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| 10. |
- Broberger, Christian, et al.
(författare)
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Differential effects of intrastriatally infused fully and endcap phosphorothioate antisense oligonucleotides on morphology, histochemistry and prodynorphin expression in rat brain
- 2000
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Ingår i: Brain Research. Molecular Brain Research. - : Elsevier BV. - 0169-328X .- 1872-6941. ; 75:1, s. 25-45
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, we investigated the selectivity and specificity associated with continuous intrastriatal treatment with antisense oligonucleotides. Rats were given intrastriatal infusions for 72 h with phosphodiester, and fully and endcap phosphorothioated oligonucleotide probes complementary to prodynorphin mRNA. Dynorphin (Dyn) peptide levels were measured by radioimmunoassay. The integrity of three other striatal transmitter systems, the neuropeptide Y (NPY)-ergic interneurons, the cholinergic interneurons and the dopaminergic afferent innervation, was assessed histochemically. The gross morphology of the striatum and the distribution of fluorescently labelled antisense probes were also investigated. Brains infused with phosphodiester probes had tissue Dyn levels not different from control. They also showed little or no change in staining for NPY, acetylcholinesterase (AChE) and tyrosine hydroxylase (TH) and essentially normal striatal gross morphology. In contrast, brains treated with fully phosphorothioated oligonucleotides showed significant decreases in striatal Dyn levels but also severe tissue damage accompanied by massive cell infiltration and decreases in immunoreactivities for the striatal neurochemical markers. Fluorescently labelled phosphorothioate probes were observed widely in the striatum and adjacent structures and, presumably retrogradely transported, in the dopamine cell bodies in the substantia nigra, also revealing the presence of abnormal cellular structures within the striatum. By comparison, endcap probes significantly reduced striatal Dyn levels and showed good tissue penetration without inducing major changes in tissue morphology or histochemistry of non-dynorphinergic systems, except for cell infiltration. The deleterious tissue effects of fully phosphorothioated oligonucleotides and the ineffectiveness of phosphodiester oligonucleotides in inhibiting protein synthesis suggest that, of the probes examined in this study, endcap oligonucleotides are the most useful for in vivo studies in the central nervous system.
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