Browsing by Subject "ANIMAL-MODELS"

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  • Ardashov, Oleg V.; Pavlova, Alla V.; Mahato, Arun Kumar; Sidorova, Yulia; Morozova, Ekaterina A.; Korchagina, Dina V.; Salnikov, Georgi E.; Genaev, Alexander M.; Patrusheva, Oksana S.; Li-Zhulanov, Nikolay S.; Tolstikova, Tat'yana G.; Volcho, Konstantin P.; Salakhutdinov, Nariman. F. (2019)
    We previously showed that monoterpenoid (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol 1 alleviates motor manifestations of Parkinson's disease in animal models. In the present study, we designed and synthesized monoepoxides of (1R,2R,6S)-3-methyl-6-(prop-1-en-2-yl)cyclohex-3-ene-1,2-diol 1 and evaluated their biological activity in the MPTP mouse model of Parkinson's disease. We also assessed the ability of these compounds to penetrate the blood-brain barrier (BBB). According to these data, we chose epoxide 4, which potently restored the locomotor activity in MPTP-treated mice and efficiently penetrated the BBB, to further explore its potential mechanism of action. Epoxide 4 was found to robustly promote the survival of cultured dopamine neurons, protect dopamine neurons against toxin-induced degeneration, and trigger the mitogen-activated protein kinase (MAPK) signaling cascade in cells of neuronal origin. Meanwhile, neither the survival-promoting effect nor MAPK activation was observed in non-neuronal cells treated with epoxide 4. In the MPTP mouse model of Parkinson's disease, compound 4 increased the density of dopamine neuron fibers in the striatum, which can highlight its potential to stimulate striatal reinnervation and thus halt disease progression. Taken together, these data indicate that epoxide 4 can be a promising compound for further development, not only as a symptomatic but also as a neuroprotective and neurorestorative drug for Parkinson's disease.
  • Kaukonen, Maria; Quintero, Ileana B.; Mukarram, Abdul Kadir; Hytönen, Marjo K.; Holopainen, Saila; Wickström, Kaisa; Kyöstilä, Kaisa; Arumilli, Meharji; Jalomäki, Sari; Daub, Carsten O.; Kere, Juha; Lohi, Hannes; Consortium, the DoGA (2020)
    Author summary Retinitis pigmentosa (RP) is a blinding eye disease that affects nearly two million people worldwide. Several genes and variants have been associated with the disease, but still 30-80% of the patients lack genetic diagnosis. There is currently no standard treatment for RP, and much is expected from gene therapy. A similar disease, called progressive retinal atrophy (PRA), affects many dog breeds. We performed clinical, genetic and functional analyses to find the genetic cause for PRA in Miniature Schnauzers. We discovered two forms of PRA in the breed, named type 1 and 2, and show that they are genetically distinct as they map to different chromosomes, 15 and X, respectively. Further genetic, bioinformatic and functional analyses discovered a fully penetrant recessive variant in a putative silencer region for type 1 PRA. Silencer regions are important for gene regulation and we found that two of its predicted target genes, EDN2 and COL9A2, were overexpressed in the retina of the affected dog. Defects in both EDN2 and COL9A2 have been associated with retinal degeneration. This study provides new insights to retinal biology while the genetic test guides better breeding choices. Retinitis pigmentosa (RP) is the leading cause of blindness with nearly two million people affected worldwide. Many genes have been implicated in RP, yet in 30-80% of the RP patients the genetic cause remains unknown. A similar phenotype, progressive retinal atrophy (PRA), affects many dog breeds including the Miniature Schnauzer. We performed clinical, genetic and functional experiments to identify the genetic cause of PRA in the breed. The age of onset and pattern of disease progression suggested that at least two forms of PRA, types 1 and 2 respectively, affect the breed, which was confirmed by genome-wide association study that implicated two distinct genomic loci in chromosomes 15 and X, respectively. Whole-genome sequencing revealed a fully segregating recessive regulatory variant in type 1 PRA. The associated variant has a very recent origin based on haplotype analysis and lies within a regulatory site with the predicted binding site of HAND1::TCF3 transcription factor complex. Luciferase assays suggested that mutated regulatory sequence increases expression. Case-control retinal expression comparison of six best HAND1::TCF3 target genes were analyzed with quantitative reverse-transcriptase PCR assay and indicated overexpression of EDN2 and COL9A2 in the affected retina. Defects in both EDN2 and COL9A2 have been previously associated with retinal degeneration. In summary, our study describes two genetically different forms of PRA and identifies a fully penetrant variant in type 1 form with a possible regulatory effect. This would be among the first reports of a regulatory variant in retinal degeneration in any species, and establishes a new spontaneous dog model to improve our understanding of retinal biology and gene regulation while the affected breed will benefit from a reliable genetic testing.
  • Keuters, Meike Hedwig; Keksa-Goldsteine, Velta; Dhungana, Hiramani; Huuskonen, Mikko T.; Pomeshchik, Yuriy; Savchenko, Ekaterina; Korhonen, Paula K.; Singh, Yajuvinder; Wojciechowski, Sara; Lehtonen, Sarka; Kanninen, Katja M.; Malm, Tarja; Sirviö, Jouni; Muona, Anu; Koistinaho, Milla; Goldsteins, Gundars; Koistinaho, Jari (2021)
    Lipid peroxidation-initiated ferroptosis is an iron-dependent mechanism of programmed cell death taking place in neurological diseases. Here we show that a condensed benzo[b]thiazine derivative small molecule with an arylthiazine backbone (ADA-409-052) inhibits tert-Butyl hydroperoxide (TBHP)-induced lipid peroxidation (LP) and protects against ferroptotic cell death triggered by glutathione (GSH) depletion or glutathione peroxidase 4 (GPx4) inhibition in neuronal cell lines. In addition, ADA-409-052 suppresses pro-inflammatory activation of BV2 microglia and protects N2a neuronal cells from cell death induced by pro-inflammatory RAW 264.7 macrophages. Moreover, ADA-409-052 efficiently reduces infarct volume, edema and expression of pro-inflammatory genes in a mouse model of thromboembolic stroke. Targeting ferroptosis may be a promising therapeutic strategy in neurological diseases involving severe neuronal death and neuroinflammation.
  • Aitta-aho, Teemu; Maksimovic, Milica; Dahl, Kristiina; Sprengel, Rolf; Korpi, Esa R. (2019)
    Gene-targeted mice with deficient AMPA receptor GluA1 subunits (Gria1-/- mice) show robust hyperlocomotion in a novel environment, suggesting them to constitute a model for hyperactivity disorders such as mania, schizophrenia and attention deficit hyperactivity disorder. This behavioral alteration has been associated with increased neuronal activation in the hippocampus, and it can be attenuated by chronic treatment with antimanic drugs, such as lithium, valproic acid, and lamotrigine. Now we found that systemic cannabidiol strongly blunted the hyperactivity and the hippocampal c-Fos expression of the Gria1-/- mice, while not affecting the wild-type littermate controls. Acute bilateral intra-dorsal hippocampal infusion of cannabidiol partially blocked the hyperactivity of the Gria1-/- mice, but had no effect on wild-types. The activation of the inhibitory DREADD receptor hM4Gi in the dorsal hippocampus by clozapine-N-oxide robustly inhibited the hyperactivity of the Gria1-/- mice, but had no effect on the locomotion of wild-type mice. Our results show that enhanced neuronal excitability in the hippocampus is associated with pronounced novelty-induced hyperactivity of GluA1 subunit-deficient mice. When this enhanced response of hippocampal neurons to novel stimuli is specifically reduced in the hippocampus by pharmacological treatment or by chemogenetic inhibition, Gria1-/- mice recover from behavioral hyperactivity, suggesting a hippocampal dysfunction in hyperactive behaviors that can be treated with cannabidiol.
  • Heinla, Indrek; Åhlgren, Johanna; Vasar, Eero; Voikar, Vootele (2018)
    Developing reliable mouse models for social behaviour is challenging. Different tests have been proposed, but most of them consist of rather artificial confrontations of unfamiliar mice in novel arenas or are relying on social stress induced by aggressive conspecifics. Natural social interaction in home cage in laboratory has not been investigated well. IntelliCage is a fully automated home-cage system, where activity of the group-housed mice can be monitored along with various cognitive tasks. Here we report the behavioural profile of C57BL/6N (86) and BALB/c (BALB) female mice in IntelliCage when separated by strain, followed by monitoring of activity and formation of 'home-base' after mixing two strains. For that purpose, 3 cages were connected. Significant differences between the strains were established in baseline behaviour in conventional tests and in IntelliCage. The B6 mice showed reduced anxiety-like behaviour in open field and light-dark box, slightly enhanced exploratory activity in IntelliCage during initial adaptation and clearly distinct circadian activity. Mixing of two strains resulted in reduction of body weight and anhedonia in B6 mice. In addition, the B6 mice showed clear preference to previous home-cage, and formed a new home-base faster than BALB mice. In contrast, BALB mice showed enhanced activity and moving between the cages without showing any preference to previous home-cage. It could be argued that social challenge caused changes in both strains and different coping styles are responsible for behavioural manifestations. Altogether, this approach could be useful in modelling and validating mouse models for disorders with disturbed social behaviour.
  • Brandt, Claudia; Seja, Patricia; Töllner, Kathrin; Römermann, Kerstin; Hampel, Philip; Kalesse, Markus; Kipper, Andi; Feit, Peter W.; Lykke, Kasper; Toft-Bertelsen, Trine Lisberg; Paavilainen, Pauliina; Spoljaric, Inkeri; Puskarjov, Martin; MacAulay, Nanna; Kaila, Kai; Löscher, Wolfgang (2018)
    Based on the potential role of Na-K-Cl cotransporters (NKCCs) in epileptic seizures, the loop diuretic bumetanide, which blocks the NKCC1 isoforms NKCC1 and NKCC2, has been tested as an adjunct with phenobarbital to suppress seizures. However, because of its physicochemical properties, bumetanide only poorly penetrates through the blood-brain barrier. Thus, concentrations needed to inhibit NKCC1 in hippocampal and neocortical neurons are not reached when using doses (0.1-0.5 mg/kg) in the range of those approved for use as a diuretic in humans. This prompted us to search for a bumetanide derivative that more easily penetrates into the brain. Here we show that bumepamine, a lipophilic benzylamine derivative of bumetanide, exhibits much higher brain penetration than bumetanide and is more potent than the parent drug to potentiate phenobarbital's anticonvulsant effect in two rodent models of chronic difficult-to-treat epilepsy, amygdala kindling in rats and the pilocarpine model in mice. However, bumepamine suppressed NKCC1-dependent giant depolarizing potentials (GDPs) in neonatal rat hippocampal slices much less effectively than bumetanide and did not inhibit GABA-induced Ca2+ transients in the slices, indicating that bumepamine does not inhibit NKCC1. This was substantiated by an oocyte assay, in which bumepamine did not block NKCC1a and NKCC1b after either extra- or intracellular application, whereas bumetanide potently blocked both variants of NKCC1. Experiments with equilibrium dialysis showed high unspecific tissue binding of bumetanide in the brain, which, in addition to its poor brain penetration, further reduces functionally relevant brain concentrations of this drug. These data show that CNS effects of bumetanide previously thought to be mediated by NKCC1 inhibition can also be achieved by a close derivative that does not share this mechanism. Bumepamine has several advantages over bumetanide for CNS targeting, including lower diuretic potency, much higher brain permeability, and higher efficacy to potentiate the anti-seizure effect of phenobarbital.
  • Kulesskaya, Natalia; Voikar, Vootele; Peltola, Marjaana; Yegutkin, Gennady G.; Salmi, Marko; Jalkanen, Sirpa; Rauvala, Heikki (2013)
  • Salonius, Eve; Rieppo, Lassi; Nissi, Mikko J.; Pulkkinen, Hertta J.; Brommer, Harold; Bruenott, Anne; Silvast, Tuomo S.; Van Weeren, P. Rene; Muhonen, Virpi; Brama, Pieter A. J.; Kiviranta, Ilkka (2019)
    Aim: The horse joint, due to its similarity with the human joint, is the ultimate model for translational articular cartilage repair studies. This study was designed to determine the critical size of cartilage defects in the equine carpus and serve as a benchmark for the evaluation of new cartilage treatment options. Material and Methods: Circular full-thickness cartilage defects with a diameter of 2, 4, and 8 mm were created in the left middle carpal joint and similar osteochondral (3.5 mm in depth) defects in the right middle carpal joint of 5 horses. Spontaneously formed repair tissue was examined macroscopically, with MR and mu CT imaging, polarized light microscopy, standard histology, and immunohistochemistry at 12 months. Results: Filling of 2 mm chondral defects was good (77.8 +/- 8.5%), but proteoglycan depletion was evident in Safranin-O staining and gadolinium-enhanced MRI (T-1Gd). Larger chondral defects showed poor filling (50.6 +/- 2.7% in 4 mm and 31.9 +/- 7.3% in 8 mm defects). Lesion filling in 2, 4, and 8 mm osteochondral defects was 82.3 +/- 3.0%, 68.0 +/- 4.6% and 70.8 +/- 15.4%, respectively. Type II collagen staining was seen in 9/15 osteochondral defects but only in 1/15 chondral defects. Subchondral bone pathologies were evident in 14/15 osteochondral samples but only in 5/15 chondral samples. Although osteochondral lesions showed better neotissue quality than chondral lesions, the overall repair was deemed unsatisfactory because of the subchondral bone pathologies. Conclusion: We recommend classifying 4 mm as critical osteochondral lesion size and 2 mm as critical chondral lesion size for cartilage repair research in the equine carpal joint model.
  • Choo, Xin Yi; Liddell, Jeffrey R.; Huuskonen, Mikko T.; Grubman, Alexandra; Moujalled, Diane; Roberts, Jessica; Kysenius, Kai; Patten, Lauren; Quek, Hazel; Oikari, Lotta E.; Duncan, Clare; James, Simon A.; McInnes, Lachlan E.; Hayne, David J.; Donnelly, Paul S.; Pollari, Eveliina; Vähätalo, Suvi; Lejavova, Katarina; Kettunen, Mikko; Malm, Tarja; Koistinaho, Jari; White, Anthony R.; Kanninen, Katja M. (2018)
    Background: Neuroinflammation and biometal dyshomeostasis are key pathological features of several neurodegenerative diseases, including Alzheimer's disease (AD). Inflammation and biometals are linked at the molecular level through regulation of metal buffering proteins such as the metallothioneins. Even though the molecular connections between metals and inflammation have been demonstrated, little information exists on the effect of copper modulation on brain inflammation. Methods: We demonstrate the immunomodulatory potential of the copper bis(thiosemicarbazone) complex Cu-II(atsm) in an neuroinflammatory model in vivo and describe its anti-inflammatory effects on microglia and astrocytes in vitro. Results: By using a sophisticated in vivo magnetic resonance imaging (MRI) approach, we report the efficacy of Cu-II(atsm) in reducing acute cerebrovascular inflammation caused by peripheral administration of bacterial lipopolysaccharide (LPS). Cu-II(atsm) also induced anti-inflammatory outcomes in primary microglia [significant reductions in nitric oxide (NO), monocyte chemoattractant protein 1 (MCP-1), and tumor necrosis factor (TNF)] and astrocytes [significantly reduced NO, MCP-1, and interleukin 6 (IL-6)] in vitro. These anti-inflammatory actions were associated with increased cellular copper levels and increased the neuroprotective protein metallothionein-1 (MT1) in microglia and astrocytes. Conclusion: The beneficial effects of Cu-II(atsm) on the neuroimmune system suggest copper complexes are potential therapeutics for the treatment of neuroinflammatory conditions.
  • Andersen, Petter I.; Ianevski, Aleksandr; Lysvand, Hilde; Oksenych, Valentyn; Bjørås, Magnar; Telling, Kaidi; Lutsar, Irja; Dampis, Uga; Irie, Yasuhiko; Tenson, Tanel; Kantele, Anu; Kainov, Denis (2020)
    Viral diseases are one of the leading causes of morbidity and mortality in the world. Virus-specific vaccines and antiviral drugs are the most powerful tools to combat viral diseases. However, broad-spectrum antiviral agents (BSAAs, i.e. compounds targeting viruses belonging to two or more viral families) could provide additional protection of the general population from emerging and re-emerging viral diseases, reinforcing the arsenal of available antiviral options. Here, we review discovery and development of BSAAs and summarize the information on 120 safe-in-man agents in a freely accessible database (https://drugvirus.info/). Future and ongoing pre-clinical and clinical studies will increase the number of BSAAs, expand the spectrum of their indications, and identify drug combinations for treatment of emerging and re-emerging viral infections as well as co-infections. (C) 2020 The Authors. Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.
  • Zhang, Christine R.; Kurniawan, Nyoman D.; Yamada, Lisa; Fleming, Whitney; Kaminen-Ahola, Nina; Ahola, Arttu; Galloway, Graham; Chong, Suyinn (2019)
    We examined whether an early-life event ethanol exposure in the initial stages of pregnancy affected offspring brain structure, energy metabolism, and body composition in later life. Consumption of 10% (v/v) ethanol by inbred C57BL/6J female mice from 0.5 to 8.5 days post coitum was used to model alcohol exposure during the first 3-4 weeks of gestation in humans, when pregnancy is not typically recognized. At adolescence (postnatal day [P] 28) and adulthood (P64), the brains of male offspring were scanned ex vivo using ultra-high field (16.4 T) magnetic resonance imaging and diffusion tensor imaging. Energy metabolism and body composition were measured in adulthood by indirect calorimetry and dual energy X-ray absorptiometry (DXA), respectively. Ethanol exposure had no substantial impact on white matter organization in the anterior commissure, corpus callosum, hippocampal commissure, internal capsule, optic tract, or thalamus. Whole brain volume and the volumes of the neocortex, cerebellum, and caudate putamen were also unaffected. Subtle, but non-significant, effects were observed on the hippocampus and the hypothalamus in adult ethanol-exposed male offspring. Ethanol exposure was additionally associated with a trend toward decreased oxygen consumption, carbon dioxide production, and reduced daily energy expenditure, as well as significantly increased adiposity, albeit with normal body weight and food intake, in adult male offspring. In summary, ethanol exposure restricted to early gestation had subtle long-term effects on the structure of specific brain regions in male offspring. The sensitivity of the hippocampus to ethanol-induced damage is reminiscent of that reported by other studies despite differences in the level, timing, and duration of exposure and likely contributes to the cognitive impairment that characteristically results from prenatal ethanol exposure. The hypothalamus plays an important role in regulating metabolism and energy homeostasis. Our finding of altered daily energy expenditure and adiposity in adult ethanol-exposed males is consistent with the idea that central nervous system abnormalities also underpin some of the metabolic phenotypes associated with ethanol exposure in pregnancy. (C) 2018 Elsevier Inc. All rights reserved.
  • Lei, Jing; Ye, Gang; Pertovaara, Antti; You, Hao-Jun (2020)
    Here we investigated variations of endogenous descending modulation of nociception and therapeutic effects of intramuscular (i.m.) heating-needle stimulation in early stage of Parkinson's disease (PD) induced by unilateral microinjection of 3.5 mu l of 2.5 mu g/mu l 6-hydroxydopamine into the rat striatum. Paw withdrawal reflexes to noxious mechanical and heat stimuli in PD rats with and without exposure to i.m. 5.8% saline induced muscle nociception were evaluated. Experimental PD had no influence on mechanical or heat sensitivity in the baseline condition, whereas descending facilitation was stronger and descending inhibition was weaker in PD rats than vehicle-treated or naive rats during muscle nociception (P <0.05). Striatal administration of 5 mu g of dopamine failed to reverse the PD-associated changes in descending facilitation or inhibition, whereas dopamine in the thalamic mediodorsal (MD) nucleus and ventromedial (VM) nucleus significantly decreased the increase in descending facilitation and reversed the attenuation in descending inhibition, respectively (P <0.05). I.m. 43 degrees C of heating-needle stimulation had no effects on the enhanced descending facilitation in PD rats, but it markedly increased descending inhibition and reversed the increase in the number of apomorphine-induced body rotations (P <0.05), which effects were dose-dependently attenuated by raclopride, a dopamine 2 receptor antagonist, in the thalamic VM nucleus (P <0.05). The results indicate that the early-stage PD is associated with enhanced descending facilitation and weakened descending inhibition. From clinical perspective, 43 degrees C heat therapeutic regime promises to selectively enhance descending inhibition that is accompanied by improvement of motor dysfunction in PD. (c) 2020 IBRO. Published by Elsevier Ltd. All rights reserved.
  • Cox, Melissa L.; Evans, Jacquelyn M.; Davis, Alexander G.; Guo, Ling T.; Levy, Jennifer R.; Starr-Moss, Alison N.; Salmela, Elina; Hytonen, Marjo K.; Lohi, Hannes; Campbell, Kevin P.; Clark, Leigh Anne; Shelton, G. Diane (2017)
    Background: Limb-girdle muscular dystrophies (LGMDs) are a heterogeneous group of inherited autosomal myopathies that preferentially affect voluntary muscles of the shoulders and hips. LGMD has been clinically described in several breeds of dogs, but the responsible mutations are unknown. The clinical presentation in dogs is characterized by marked muscle weakness and atrophy in the shoulder and hips during puppyhood. Methods: Following clinical evaluation, the identification of the dystrophic histological phenotype on muscle histology, and demonstration of the absence of sarcoglycan-sarcospan complex by immunostaining, whole exome sequencing was performed on five Boston terriers: one affected dog and its three family members and one unrelated affected dog. Results: Within sarcoglycan-delta (SGCD), a two base pair deletion segregating with LGMD in the family was discovered, and a deletion encompassing exons 7 and 8 was found in the unrelated dog. Both mutations are predicted to cause an absence of SGCD protein, confirmed by immunohistochemistry. The mutations are private to each family. Conclusions: Here, we describe the first cases of canine LGMD characterized at the molecular level with the classification of LGMD2F.
  • Ridolfo, Roxane; Tavakoli, Shirin; Junnuthula, Vijayabhaskarreddy; Williams, David S.; Urtti, Arto; van Hest, Jan C. M. (2021)
    Nanoparticle morphology (size, shape, and composition) and surface chemistry are the determining factors underpinning the efficacy of such materials in therapeutic applications. The size, shape, and surface chemistry of a nanoparticle can strongly influence key properties such as interactions with diverse biological fluids and interfaces and, in turn, impact the delivery of bioactive cargo, modulating therapeutic performance. This is exemplified in ocular drug delivery, where potential therapeutics must navigate complex biological media such as the gel-like vitreal fluid and the retina. Biodegradable block copolymer amphiphiles are a robust tool for the engineering of various types of self-assembled nanoparticles with diverse morphologies ranging from spherical and tubular polymersomes to spherical and worm-like micelles. Here, we explore the effect of morphological features such as shape and surface chemistry upon the interactions of a series of copolymer nanoparticles with retinal (ARPE-19) cells and the release of a low solubility drug (dexamethasone) that is currently used in ocular therapy and study their diffusion in vitreous using ex vivo eyes. We demonstrate that both aspect ratio and surface chemistry of nanoparticles will influence their performance in terms of cell uptake, drug release, and diffusion with high aspect ratio shapes demonstrating enhanced properties in relation to their spherical counterparts.
  • Puurunen, Jenni; Tiira, Katriina; Vapalahti, Katariina; Lehtonen, Marko; Hanhineva, Kati; Lohi, Hannes (2018)
    Anxiety-related disorders, including fearfulness are common and leading welfare problems among the worldwide dog population. The etiology of anxieties is complex and affected by genetic and environmental factors. Thus, there is a need for more comprehensive approaches, such as metabolomics, to understand the causes of anxiety and to identify anxiety-related biomarkers for more efficient diagnostic and treatment options. To study metabolic alterations related to canine fearfulness, a non-targeted plasma metabolite profiling was performed in a cohort of 20 fearful and 21 non-fearful dogs. The results showed that nine metabolic features were significantly associated with fearfulness. The most prominent change included increased plasma glutamine and gamma-glutamyl glutamine (gamma-Glu Gln) in fearful dogs across breeds. Alterations in glutamine metabolism have previously been associated with several psychiatric disorders, indicating the relevance of this finding also in dogs. In addition, we describe a novel breed-specific association between renal biomarker symmetric dimethylarginine (SDMA) and canine fearfulness. These observed metabolic alterations may result from high levels of prolonged psychological stress in fearful dogs.
  • Amorim, Diana; Viisanen, Hanna; Wei, Hong; Almeida, Armando; Pertovaara, Antti; Pinto-Ribeiro, Filipa (2015)
    Activation of the dorsomedial nucleus of the hypothalamus (DMH) by galanin (GAL) induces behavioural hyperalgesia. Since DMH neurones do not project directly to the spinal cord, we hypothesized that the medullary dorsal reticular nucleus (DRt), a pronociceptive region projecting to the spinal dorsal horn (SDH) and/or the serotoninergic raphe-spinal pathway acting on the spinal 5-HT3 receptor (5HT(3)R) could relay descending nociceptive facilitation induced by GAL in the DMH. Heat-evoked paw-withdrawal latency (PWL) and activity of SDH neurones were assessed in monoarthritic (ARTH) and control (SHAM) animals after pharmacological manipulations of the DMH, DRt and spinal cord. The results showed that GAL in the DMH and glutamate in the DRt lead to behavioural hyperalgesia in both SHAM and ARTH animals, which is accompanied particularly by an increase in heat-evoked responses of wide-dynamic range neurons, a group of nociceptive SDH neurones. Facilitation of pain behaviour induced by GAL in the DMH was reversed by lidocaine in the DRt and by ondansetron, a 5HT(3)R antagonist, in the spinal cord. However, the hyperalgesia induced by glutamate in the DRt was not blocked by spinal ondansetron. In addition, in ARTH but not SHAM animals PWL was increased after lidocaine in the DRt and ondansetron in the spinal cord. Our data demonstrate that GAL in the DMH activates two independent descending facilitatory pathways: (i) one relays in the DRt and (ii) the other one involves 5-HT neurones acting on spinal 5HT(3)Rs. In experimental ARTH, the tonic pain-facilitatory action is increased in both of these descending pathways.
  • Ribeiro, Deidiane Elisa; Casarotto, Plinio C.; Staquini, Laura; Pinto e Silva, Maria Augusta; Biojone, Caroline; Wegener, Gregers; Joca, Samia (2019)
    Purinergic receptors, especially P2RX, are associated to the severity of symptoms in patients suffering from depressive and bipolar disorders, and genetic deletion or pharmacological blockade of P2RX7 induces antidepressant-like effect in preclinical models. However, there is scarce evidence about the alterations in P2RX7 or P2RX4 levels and in behavioral consequences induced by previous exposure to stress, a major risk factor for depression in humans. In the present study, we evaluated the effect of imipramine (IMI) on P2RX7 and P2RX4 levels in dorsal and ventral hippocampus as well as in the frontal cortex of rats submitted to the pretest session of learned helplessness (LH) paradigm. Repeated, but not acute administration of IMI (15 mg/kg ip) reduced the levels of both P2RX7 and P2RX4 in the ventral, but not in dorsal hippocampus or frontal cortex. In addition, we tested the effect of P2RX7/ P2RX4 antagonist brilliant blue G (BBG: 25 or 50 mg/kg ip) on the LH paradigm. We observed that repeated (7 days) but not acute (1 day) treatment with BBG (50 mg) reduced the number of failures to escape the shocks in the test session, a parameter mimicked by the same regimen of IMI treatment. Taken together, our data indicates that pharmacological blockade or decrease in the expression of P2RX7 is associated to the antidepressant-like behavior observed in the LH paradigm after repeated drug administration.
  • Uhari-Väänänen, Johanna; Eteläinen, Tony; Bäckström, Pia; Oinio, Ville; Carroll, F. Ivy; Raasmaja, Atso; Kiianmaa, Kalervo; Piepponen, Petteri (2019)
    The mechanisms behind relapse to ethanol intake in recovering alcoholics are still unclear. The negative reinforcing effects contributing to ethanol addiction, including relapse, are considered to be partly driven by the kappa-opioidergic system. As the kappa-opioidergic system interacts with the mesolimbic reward pathway, the aim of the study was to clarify the role of nucleus accumbens shell kappa-opioidergic mechanisms in relapse to ethanol intake by using the alcohol deprivation effect (ADE) paradigm. The ADE is defined as a transient increase in voluntary ethanol intake after a forced period of abstinence. Male Long-Evans rats were trained to voluntarily consume 10% (v/v) ethanol solution. Ethanol access and deprivation cycles were initiated after stable ethanol intake baselines had been reached and bilateral guide cannulas had been implanted above the nucleus accumbens shell. One cycle consisted of 10 days of 90 min access to ethanol followed by 6 days of ethanol deprivation. The ADE was measured in the beginning of a new cycle. Rats received JDTic, a selective kappa-antagonist, either subcutaneously (10 mg/kg) or intra-accumbally (15 mu g/site) or, as a reference substance, systemic naltrexone (0.3 mg/kg) before ethanol re-access, and the effects on the ADE were evaluated. Systemic and intra-accumbal JDTic significantly attenuated the ADE on the first day of ethanol re-access, as did systemic naltrexone. Additionally, naltrexone decreased ethanol intake levels. These results suggest that nucleus accumbens shell kappa-opioidergic mechanisms may have a role in mediating relapse to ethanol intake. Additionally, kappa-antagonism could be a valuable adjunct in ethanol relapse prevention. (C) 2019 Elsevier B.V. and ECNP. All rights reserved.
  • Vesikansa, Aino (2018)
    The complex structure and highly variable gene expression profile of the brain makes it among the most challenging fields to study in both basic and translational biological research. Most of the brain diseases are multifactorial and despite the rapidly increasing genomic data, molecular pathways and causal links between genes and central nervous system (CNS) diseases are largely unknown. The advent of an easy and flexible CRISPR-Cas genome editing technology has rapidly revolutionized the field of functional genomics and opened unprecedented possibilities to dissect the mechanisms of CNS disease. CRISPR-Cas allows a plenitude of applications for both gene-focused and genome-wide approaches, ranging from original "gene scissors" making permanent modifications in the genome to the regulation of gene expression and epigenetics. CRISPR technology provides a unique opportunity to establish new cellular and animal models of CNS diseases and holds potential for breakthroughs in the CNS research and drug development.