| 1. |
- Guillery, Ray, et al.
(author)
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Editorial note
- 1990
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In: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 2:7, s. 565-565
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Journal article (peer-reviewed)
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| 2. |
- Cenci Nilsson, Angela, et al.
(author)
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Striatal c-fos Induction by Cocaine or Apomorphine Occurs Preferentially in Output Neurons Projecting to the Substantia Nigra in the Rat
- 1992
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In: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 4:4, s. 376-380
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Journal article (peer-reviewed)abstract
- Fluorogold or rhodamine-labelled latex beads were injected in the substantia nigra (SN) or the globus pallidus (GP) in order retrogradely to label striatal output neurons that project to the two target structures. Ten days later, striatal c-fos was induced by systemic administration of cocaine (five normal rats; 25 mg/kg cocaine i.p. 2 h before killing) or apomorphine (five unilaterally dopamine-denervated rats; 0.25 mg/kg apomorphine s. c. 2 h before killing), and detection of the Fos protein in the striatum was achieved by immunofluorescence. Sections through the caudate-putamen that displayed good labelling from both SN and GP were selected for a quantitative analysis: the number of retrogradely labelled cells that exhibited Fos immunoreactivity, as well as the total number of retrogradely labelled cells located within a grid (0.16 mm2 in size) were counted manually at 25 x magnification. Cocaine induced a proportionally higher c-fos expression in striato-nigral compared to striato-pallidal neurons, whereas apomorphine activated Fos almost exclusively in striato-nigral neurons. The present findings are consistent with the idea that striatal c-fos induction by dopaminergic agents is primarily mediated by an interaction with D1-receptors, which are thought to be selectively localized on neurons projecting to SN.
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| 3. |
- Garwicz, Martin, et al.
(author)
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Distribution of Cutaneous Nociceptive and Tactile Climbing Fibre Input to Sagittal Zones in Cat Cerebellar Anterior Lobe
- 1992
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In: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 4:4, s. 289-295
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Journal article (peer-reviewed)abstract
- Climbing fibres projecting to the cerebellar C3 zone (and the related C1 and Y zones) receive spatially well organized tactile and nociceptive inputs from the skin. In the present study, cutaneous tactile and nociceptive input to climbing fibres projecting to the X, B, C2 and D1 zones in lobule V were investigated in pentobarbitone-anaesthetized cats. From the present results and previous studies, it is concluded that the X, C1, CX, C3 and Y zones receive cutaneous nociceptive climbing fibre input. By contrast, climbing fibres to the B, C2 and D1 zones lack cutaneous nociceptive input. Tactile input was found in all zones. The spatial organization of receptive fields of climbing fibres projecting to the X and D1 zones was similar to that in the C3 zone. They were located on the ipsilateral forelimb, mainly its lateral and distal parts, and their proximal borders were located close to joints. In the B zone, more than half of the receptive fields of climbing fibres were confined to the ipsilateral hind- or forelimb. However, frequently more than one limb and parts of the trunk were included. In the C2 zone, the majority of climbing fibres had distal ipsi- or bilateral receptive fields on the forelimbs, often also including the head/face. Some of the bilateral forelimb receptive fields additionally included the hindlimbs ipsi- or bilaterally. The results indicate that each zone has a characteristic set of climbing fibre receptive fields, which is probably related to its efferent control functions.
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| 4. |
- Kalén, Peter, et al.
(author)
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Host Brain Regulation of Fetal Locus Coeruleus Neurons Grafted to the Hippocampus in 6-Hydroxydopamine-Treated Rats. An Intracerebral Microdialysis Study
- 1991
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In: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 3:9, s. 905-918
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Journal article (peer-reviewed)abstract
- Release properties of intrahippocampal transplants of noradrenergic neurons were monitored by microdialysis in awake and halothane-anaesthetized rats. Fetal locus coeruleus neurons were implanted as a cell suspension into hippocampi deprived of their innate noradrenalin (NA) innervation by intraventricular 6-hydroxydopamine treatment. Dialysis probes of the loop type were implanted into the dorsal hippocampus 1 - 2 days before each experiment, i.e. 7 - 11 months after grafting. Age-matched intact and lesion-only animals served as controls. Microscopic analysis showed a graft-derived tyrosine hydroxylase immunoreactive, presumably noradrenergic, fibre network throughout the dorsal hippocampal formation, surrounding the probe site. The innervation density varied from sub- to supranormal. The grafts restored baseline NA release in the graft-reinnervated hippocampus to near-normal levels both in awake and halothane-anaesthetized animals. Potassium chloride (100 mM) in the perfusion fluid induced a dramatic increase in NA release that was similar in magnitude in the grafted and intact hippocampi. A NA uptake blocker (desipramine) added to the perfusion fluid at 5 microM induced a similar increase in NA output in the grafted and intact hippocampi, and the output was substantially reduced by tetrodotoxin, added at 1 microM in the presence of uptake blockade. Electrical stimulation of the lateral habenular nucleus (15 Hz, 0.5 mA) in halothane-anaesthetized rats induced a significant increase in NA output both in the intact and grafted hippocampi. This effect was abolished by transection of the fasciculus retroflexus, which carries the efferent projections of the habenular complex. Behavioural activation through handling induced a consistent increase in NA release only in the intact animals, but in a few grafted rats (which also responded to habenular stimulation) the NA output was clearly elevated by handling. Forced immobilization induced a significant increase in NA output both in the intact and grafted hippocampi, but in the grafted ones the response was somewhat smaller and more transient. In the same set of animals, swimming in warm water (25 - 30 degrees C) induced a sharp increase in NA output in the intact animals, whereas only one of the grafted rats responded by increased NA output. The results indicate that the locus coeruleus grafts, despite their ectopic location, can become functionally integrated with the host brain, and that the activity of the transplanted noradrenergic neurons can, under some circumstances, be modulated from the host brain in response to environmental challenges.
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| 5. |
- Kalliomäki, J, et al.
(author)
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Differential effects of a distant noxious stimulus on hindlimb nociceptive withdrawal reflexes in the rat.
- 1992
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In: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 4:7, s. 648-652
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Journal article (peer-reviewed)abstract
- Recent studies indicate that the nociceptive withdrawal reflexes to individual muscles are evoked by separate reflex pathways. The present study examines whether nociceptive withdrawal reflexes to different muscles are subject to differential supraspinal control in rats. A distant noxious stimulus was used to activate a bulbospinal system which selectively inhibits ‘multireceptive’ neurons (i.e. neurons receiving excitatory tactile and nociceptive inputs) in the dorsal horn of the spinal cord. Withdrawal reflexes, recorded with electromyographic techniques in single hindlimb muscles, were evoked by standardized noxious pinch. Thirty‐seven rats, anaesthetized with halothane and nitrous oxide, were used. Whereas withdrawal reflexes to the extensor digitorum longus and brevis, tibialis anterior and biceps posterior muscles were strongly inhibited, reflexes to interossei muscles were potentiated during noxious pinch of the nose. Reflexes to peronei muscles were not significantly changed. The effects on the reflexes usually had an onset latency of <0.5 s and outlasted the conditioning stimulation by up to 2 s. The monosynaptic la reflex to the deep peroneal nerve, innervating dorsiflexors of the digits and ankle, was not significantly changed during noxious pinch of the nose. Hence, the inhibitory effects on the hindlimb withdrawal reflexes induced by the conditioning stimulation were presumably exerted on reflex interneurons. It is concluded that nociceptive withdrawal reflexes to different hindlimb muscles are differentially controlled by descending pathways activated by a distant noxious stimulus. The results support our previous conclusion that there are separate nociceptive withdrawal reflex pathways to different hindlimb muscles.
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| 6. |
- Kokaia, Zaal, et al.
(author)
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Brain insults in rats induce increased expression of the BDNF gene through differential use of multiple promoters
- 1994
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In: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 6:4, s. 587-596
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Journal article (peer-reviewed)abstract
- The rat brain-derived neurotrophic factor (BDNF) gene consists of four short 5'-exons linked to separate promoters and one 3'-exon encoding the mature BDNF protein. Using in situ hybridization we demonstrate here that kindling-induced seizures, cerebral ischaemia and insulin-induced hypoglycaemic coma increase BDNF mRNA levels through insult- and region-specific usage of three promoters within the BDNF gene. Both brief (2 min) and longer (10 min) periods of forebrain ischaemia induced significant and major increases only of exon III mRNA in the dentate gyrus. Following hypoglycaemic coma (1 and 30 min), exon III mRNA was markedly elevated in the dentate gyrus and, in addition, exon I mRNA showed a moderate increase. Single and recurrent (n = 40) hippocampal seizures significantly increased expression of exon I, II and III mRNAs in the dentate gyrus granule cells. After recurrent seizures, including generalized convulsions, there were also major increases of both exon I and III mRNAs in the CA3 region, amygdala, piriform cortex and neocortex, whereas in the hippocampal CA1 sector marked elevations were detected only for exon III mRNA. The insults had no effect on the level of exon IV mRNA in the brain. The region- and insult-specific pattern of promoter activation might be of importance for the effectiveness of protective responses as well as for the regulation of plastic changes following brain insults.
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| 7. |
- Mandel, Ronald J., et al.
(author)
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The Importance of Graft Placement and Task Complexity for Transplant-Induced Recovery of Simple and Complex Sensorimotor Deficits in Dopamine Denervated Rats
- 1990
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In: European Journal of Neuroscience. - : Wiley. - 1460-9568 .- 0953-816X. ; 2:10, s. 888-894
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Journal article (peer-reviewed)abstract
- The present study examined the role of graft placement and behavioural task complexity in determining the functional efficacy of intrastriatal grafts of dopamine-rich fetal ventral mesencephalon (VM) placed in the dopamine (DA) depleted striatum. The functional effects of two different striatal placements of VM grafts were evaluated using tests of drug-induced motor asymmetry, simple sensorimotor orienting response, and a more complex sensorimotor integrative task (disengage behaviour), in which the rat has to perform the orienting response while in the act of eating. Rats with complete unilateral 6-hydroxydopamine (6-OHDA) lesions of the mesostriatal DA pathway, received either implants of dissociated fetal VM in the central or ventrolateral portions of the denervated striatum. Nongrafted lesioned rats served as controls. Nine weeks after grafting, the rats were tested on separate days for disengage behaviour, sensorimotor orientation, and amphetamine-induced rotational behaviour. Consistent with previous findings, the two graft placements had differential effects on drug-induced motor asymmetry and sensorimotor responses: the centrally placed VM grafts reversed amphetamine-induced rotational asymmetry but had little effect on the sensorimotor deficit, whereas the ventrolaterally placed grafts reversed the sensorimotor orientation deficits without any effect on the drug-induced rotation. In contrast, fetal VM grafts, regardless of their placement, did not ameliorate the observed deficits in disengage behaviour; that is the grafted rats that had recovered their sensorimotor response in the absence of food were unable to perform the same orienting response while eating. These results provide evidence that functional intrastriatal VM grafts which are capable of restoring sensorimotor responses or motor asymmetry fail to affect lesion-induced deficits in a task that requires more complex sensorimotor integration. It is suggested that the degree of anatomical integration of the grafted DA neurons into the host circuitry will determine the efficacy of the grafts to influence more complex sensorimotor integrative deficits in the DA lesion model.
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| 8. |
- Jankowska, Elzbieta, et al.
(author)
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Effects of Monoamines on Transmission from Group II Muscle Afferents in Sacral Segments in the Cat Szabo Läckberg, Z. & Dyrehag, L.E.
- 1994
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In: European Journal of Neuroscience. - : Wiley. - 0953-816X .- 1460-9568. ; 6, s. 1058-1061
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Journal article (peer-reviewed)abstract
- The effects of one 5‐HT1A serotonin agonist (8‐OH‐DPAT) and of two α2 noradrenaline agonists (tizanidine and B‐HT 933) were tested on the transmission between group II muscle afferents and spinal neurons in the sacral segments of the spinal cord in the cat. These agonists have previously been found to depress transmission from group II muscle afferents either in the dorsal horn or in the intermediate zone of midlumbar segments, and this study addressed the question of whether their actions in the sacral segments are similarly selective. The drugs were applied ionophoretically and their effects were tested on field potentials evoked from group II muscle afferents. As judged by changes in the amplitude of the early components of these field potentials, the transmission is effectively depressed by the serotonin agonist (to 56 ± 26% after 2 min of ionophoresis of 8‐OH‐DPAT) but not by the noradrenaline agonists (to 97 ± 12% after 6 min of ionophoresis of B‐HT 933 and to 95 ± 17% after 6 min of ionophoresis of tizanidine). These data suggest that transmission from group II muscle spindle afferents in the sacral segments is under control of serotonin releasing neurons, as in the dorsal horn of midlumbar segments, but leave open the question of the similarities or differences in the mechanisms (pre‐and/or postsynaptic) of this control. Copyright © 1994, Wiley Blackwell. All rights reserved
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| 9. |
- Smits, Anja, et al.
(author)
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PDGF-BB exerts trophic activity on cultured GABA interneurons from the newborn rat cerebellum.
- 1993
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In: European Journal of Neuroscience. - 0953-816X .- 1460-9568. ; 5:8, s. 986-94
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Journal article (peer-reviewed)abstract
- Platelet-derived growth factor (PDGF) is a well known mitogen for mesenchyme-derived cells and glial cells. Its presence in neuronal cells of the central nervous system has only recently been described. We have shown earlier that neurons of newborn rat brains in culture express PDGF beta-receptors and that PDGF-BB, a homodimer of PDGF B-chain, increases survival and promotes neurite outgrowth of newborn cerebellar cells (Smits et al., Proc. Natl Acad. Sci. USA, 88, 8159-8163, 1991). In this study, the effects of PDGF on early postnatal rat cerebellar cells were further explored. By using chemically defined serum-free medium, we have established primary cell cultures of rat cerebella (postnatal day 4-5) containing 70-80% neuronal cells. During the first 10 days in vitro, no difference in total cell number was found between PDGF-BB-treated and untreated cultures. After this time period, however, increased survival of the PDGF-BB-treated cells was found. Within the first 10 days in vitro, the addition of PDGF-BB to the cultures resulted in a relative increase in survival of interneurons expressing glutamic acid decarboxylase (GAD), the GABA biosynthetic enzyme. Moreover, addition of PDGF-BB in the untreated cell culture resulted in a rapid increase of GAD mRNA. These results show that PDGF-BB acts as a trophic factor on GABAergic interneurons of the cerebellum by up-regulating GAD synthesis and prolonging the survival of these cells. Furthermore, in situ hybridization revealed that there are scattered cells present in the early postnatal cerebellum that express PDGF beta-receptor mRNA.
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