Journal of chemical neuroanatomy

Publications in this journal

• Article: Deep brain stimulation of the mediodorsal thalamic nucleus yields increases in the expression of zif-268 but not c-fos in the frontal cortex.

  Samuel G Ewing, Bernd Porr, Judith A Pratt
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  ABSTRACT: This study explores the regions activated by deep brain stimulation of the mediodorsal thalamic nucleus through examination of immediate early genes as markers of neuronal activation. Stimulation was delivered unilaterally with constant current 100μs duration pulses at a frequency of 130Hz delivered at an amplitude of 200μA for 3hours. Brains were removed, sectioned and radio-labeled for the IEGs zif-268 and c-fos. In anaesthetised rats, deep brain stimulation of mediodorsal thalamic nucleus produced robust increases in the expression of zif-268 but not c-fos localised to regions that are reciprocally connected with the mediodorsal thalamic nucleus, including the prelimbic and orbitofrontal cortices, and the premotor cortex indicating an increase in synaptic activity in these regions. These findings map those brain regions that are persistently, rather than transiently, activated by high frequency electrical stimulation of the mediodorsal thalamic nucleus by a putatively antidromic mechanism which may be relevant to neuropsychiatric disorders such as schizophrenia in which thalamocortical systems are disrupted and in which DBS protocols are being considered.
  Journal of chemical neuroanatomy 05/2013;
• Article: Changes of calcium binding proteins, c-Fos and COX in hippocampal formation and cerebellum of Niemann Pick, type C mouse.

  Kyunghee Byun, Daesik Kim, Enkhjaigal Bayarsaikhan, Jeehyun Oh, Jisun Kim, Grace Kwak, Goo-Bo Jeong, Seung-Mook Jo, Bonghee Lee
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  ABSTRACT: Niemann-Pick disease, type C (NPC) is an intractable disease that is accompanied by ataxia, dystonia, neurodegeneration, and dementia due to an NPC gene defect. Disruption of calcium homeostasis in neurons is important in patients with NPC. Thus, we used immunohistochemistry to assess the expression levels of calcium binding proteins (calbindin D28K, parvalbumin, and calretinin), c-Fos and cyclooxygenase-1,2 (COX-1,2) in the hippocampal formation and cerebellum of 4 and 8 week old NPC+/+, NPC+/-, and NPC-/- mice. General expression of these proteins decreased in the hippocampus and cerebellum of NPC-/- compared to that in both young and adult NPC+/+ or NPC+/- mice. Parvalbumin, COX-1,2 or c-Fos-immunoreactive neurons were widely detected in the CA1, CA3, and DG of the hippocampus, but the immunoreactivities were decreased sharply in all areas of hippocampus of NPC-/- compared to NPC+/+ and NPC+/- mice. Taken together, reduction of these proteins may be one of the strong phenotypes related to the neuronal degeneration in NPC-/- mice.
  Journal of chemical neuroanatomy 05/2013;
• Article: Coordinate regulation of noradrenergic and serotonergic brain regions by amygdalar neurons.

  T A Retson, E J Van Bockstaele
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  ABSTRACT: Based on the importance of the locus coeruleus-norepinephrine (LC-NE) system and the dorsal raphe nucleus-serotonergic (DRN-5-HT) system in stress-related pathologies, additional understanding of brain regions coordinating their activity is of particular interest. One such candidate is the amygdalar complex, and specifically, the central nucleus (CeA), which has been implicated in emotional arousal and is known to send monosynaptic afferent projections to both these regions. Our present data using dual retrograde tract tracing is the first to demonstrate a population of amygdalar neurons that project in a collateralized manner to the LC and DRN, indicating that amygdalar neurons are positioned to coordinately regulate the LC and DRN, and links these brain regions by virtue of a common set of afferents. Further, we have also characterized the phenotype of a population of these collaterally projecting neurons from the amygdala as containing corticotropin releasing factor or dynorphin, two peptides heavily implicated in the stress response. Understanding the co-regulatory influences of this limbic region on 5HT and NE regions may help fill a gap in our knowledge regarding neural circuits impacting these systems and their adaptations in stress.
  Journal of chemical neuroanatomy 05/2013;
• Article: The Edinger-Westphal nucleus II: hypothalamic afferents in the rat.

  André V da Silva, Kelly R Torres, Carlos A Haemmerle, Isabel C Céspedes, Jackson C Bittencourt
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  ABSTRACT: Numerous functions have been attributed to the Edinger-Westphal nucleus (EW), including those related to feeding behavior, pain control, alcohol consumption and the stress response. The EW is thought to consist of two parts: one controls accommodation, choroidal blood flow and pupillary constriction, primarily comprising cholinergic cells and projecting to the ciliary ganglion; and the other would be involved in the non-ocular functions mentioned above, comprising peptide-producing neurons and projecting to the brainstem, spinal cord and prosencephalic regions. Despite the fact that the EW is well known, its connections have yet to be described in detail. The aim of this work was to produce a map of the hypothalamic sources of afferents to the EW in the rat. We injected the retrograde tracer Fluoro-Gold into the EW, and using biotinylated dextran amine, injected into afferent sources as the anterograde control. We found retrogradely labeled cells in the following regions: subfornical organ, paraventricular hypothalamic nucleus, arcuate nucleus, lateral hypothalamic area, zona incerta, posterior hypothalamic nucleus, medial vestibular nucleus and cerebellar interpositus nucleus. After injecting BDA into the paraventricular hypothalamic nucleus, lateral hypothalamic area and posterior hypothalamic nucleus, we found anterogradely labeled fibers in close apposition to and potential synaptic contact with urocortin 1-immunoreactive cells in the EW. On the basis of our findings, we can suggest that the connections between the EW and the hypothalamic nuclei are involved in controlling stress responses and feeding behavior.
  Journal of chemical neuroanatomy 04/2013;
• Article: A neuroanatomical and neurochemical study of the indusium griseum and anterior hippocampal continuation: Comparison with dentate gyrus.

  François Laplante, Ouissame Mnie-Filali, Ron Sullivan
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  ABSTRACT: The indusium griseum (IG) and anterior hippocampal continuation (AHC) are longitudinal and continuous structures that consist of two narrow strips of gray matter overlying the rostrocaudal length of the corpus callosum, extending rostrally to the genu of the corpus callosum and ventrally to the rostrum. The present study aimed to characterize the phenotype of neuronal innervations to the IG-AHC and their intra-structural topographic organization. Using immunohistochemistry, we found nerve fibres expressing choline acetyltransferase, tyrosine hydroxylase, dopamine-β-hydroxylase, the serotonin reuptake transporter as well as glutamic acid decarboxylase-67 and parvalbumin. These suggest that the IG and AHC are innervated by acetylcholine, dopamine, noradrenaline, 5-hydroxytryptamine and GABA neurons. More importantly, all these fibres display a topographic laminar distribution in both brain areas. The presence of varicosities along the nerve fibres suggests that these neurotransmitters are released extracellullarly to exert a physiological action. Finally, the structural similarities with the dentate gyrus support the idea that the IG and AHC are anatomically associated, if not continuous, with this area and may represent in mammals a vestige of the hippocampus.
  Journal of chemical neuroanatomy 04/2013;
• Article: Cocaine- and amphetamine-regulated transcript (CART) peptide immunoreactivity in feeding- and reward-related brain areas of young OLETF rats.

  Simon Armbruszt, Hajnalka Abraham, Maria Figler, Tamas Kozicz, Andras Hajnal
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  ABSTRACT: Cocaine- and amphetamine regulated transcript (CART) peptide is expressed in brain areas involved in the control of appetite, drug reward and homeostatic regulation and it has an overall anorexigenic effect. Recently, we have shown that CART peptide immunoreactivity was significantly reduced in the rostral part of the nucleus accumbens and in the rostro-medial part of the nucleus of the solitary tract in adult CCK-1 receptor deficient obese diabetic Otsuka Long Evans Tokushima Fatty (OLETF) rats compared to Long Evans Tokushima Otsuka (LETO) lean controls. It is not clear, however, whether altered CART expression is caused primarily by the deficiency in CCK-1 signaling or whether is related to the obese and diabetic phenotype of the OLETF strain which develops at a later age. Therefore, in the present study, CART-immunoreaction in feeding-related areas of the brain was compared in young, age-matched (6-7 weeks old) non-obese, non-diabetic OLETF rats and in LETO controls. We found that, young, non-diabetic OLETF rats revealed unaltered distribution of CART-peptide expressing neurons and axons throughout the brain when compared to age-matched LETO rats. In contrast to previous results observed in the obese diabetic adult rats, intensity of CART immunoreaction did not differ in the areas related to control of food-intake and reward in the young OLETFs compared to young LETO rats. Our findings suggest that factors secondary to obesity and/or diabetes rather than impaired CCK-1 receptor signaling may contribute to altered CART expression in the OLETF strain.
  Journal of chemical neuroanatomy 03/2013;
• Article: Differential expression of vesicular glutamate transporters 1 and 2 may identify distinct modes of glutamatergic transmission in the macaque visual system.

  Pooja Balaram, Troy A Hackett, Jon H Kaas
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  ABSTRACT: Glutamate is the primary neurotransmitter utilized by the mammalian visual system for excitatory neurotransmission. The sequestration of glutamate into synaptic vesicles, and the subsequent transport of filled vesicles to the presynaptic terminal membrane, is regulated by a family of proteins known as vesicular glutamate transporters (VGLUTs). Two VGLUT proteins, VGLUT1 and VGLUT2, characterize distinct sets of glutamatergic projections between visual structures in rodents and prosimian primates, yet little is known about their distributions in the visual system of anthropoid primates. We have examined the mRNA and protein expression patterns of VGLUT1 and VGLUT2 in the visual system of macaque monkeys, an Old World anthropoid primate, in order to determine their relative distributions in the superior colliculus, lateral geniculate nucleus, pulvinar complex, V1 and V2. Distinct expression patterns for both VGLUT1 and VGLUT2 identified architectonic boundaries in all structures, as well as anatomical subdivisions of the superior colliculus, pulvinar complex, and V1. These results suggest that VGLUT1 and VGLUT2 clearly identify regions of glutamatergic input in visual structures, and may identify common architectonic features of visual areas and nuclei across the primate radiation. Additionally, we find that VGLUT1 and VGLUT2 characterize distinct subsets of glutamatergic projections in the macaque visual system; VGLUT2 predominates in driving or feedforward projections from lower order to higher order visual structures while VGLUT1 predominates in modulatory or feedback projections from higher order to lower order visual structures. The distribution of these two proteins suggests that VGLUT1 and VGLUT2 may identify class 1 and class 2 type glutamatergic projections within the primate visual system (Sherman and Guillery, 2006).
  Journal of chemical neuroanatomy 03/2013;
• Article: Projections from the rat cuneiform nucleus to the a7, a6 (locus coeruleus), and a5 pontine noradrenergic cell groups.

  Dusica Bajic, Herbert K Proudfit
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  ABSTRACT: Stimulation of neurons in the cuneiform nucleus (CnF) produces antinociception and cardiovascular responses that could be mediated, in part, by noradrenergic neurons that innervate the spinal cord dorsal horn. The present study determined the projections of neurons in the CnF to the pontine noradrenergic neurons in the A5, A6 (locus coeruleus), and A7 cell groups that are known to project to the spinal cord. Injections of the anterograde tracer, biotinylated dextran amine in the CnF of Sasco Sprague-Dawley rats labeled axons located near noradrenergic neurons that were visualized by processing tissue sections for tyrosine hydroxylase-immunoreactivity. Anterogradely-labeled axons were more dense on the side ipsilateral to the BDA deposit. Both A7 and A5 cell groups received dense projections from neurons in the CnF, whereas locus coeruleus received only a sparse projection. Highly varicose anterogradely-labeled axons from the CnF were found in close apposition to dendrites and somata of tyrosine hydroxylase-immunoreactive neurons in pontine tegmentum. Although definitive evidence for direct pathways from CnF neurons to the pontine noradrenergic cell groups requires ultrastructural analysis, the results of the present studies provide presumptive evidence of direct projections from neurons in the CnF to the pontine noradrenergic neurons of the A7, locus coeruleus, and A5 cell groups. These results support the suggestion that the analgesia and cardiovascular responses produced by stimulation of neurons in the CnF may be mediated, in part, by pontine noradrenergic neurons.
  Journal of chemical neuroanatomy 03/2013;
• Article: Nuclear organisation of some immunohistochemically identifiable neural systems in three Afrotherian species-Potomogale velox, Amblysomus hottentotus and Petrodromus tetradactylus.

  Tanya Calvey, Nina Patzke, Consolate Kaswera, Emmanuel Gilissen, Nigel C Bennett, Paul R Manger
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  ABSTRACT: The present study describes the organization of the cholinergic, catecholaminergic, and serotonergic neurons in the brains of the giant otter shrew, the Hottentot golden mole and the four-toed sengi, and the orexinergic (hypocretinergic) system in the giant otter shrew and four-toed sengi. The aim of the present study was to investigate the possible differences in the nuclear complement of these neural systems in comparison to previous studies on other Afrotherian species and mammalian species in general. Brains of the golden mole, sengi and giant otter shrew were coronally sectioned and immunohistochemically stained with antibodies against cholineacetyl-transferase, tyrosine hydroxylase, serotonin and orexin-A. The majority of nuclei revealed in the current study were similar among the species investigated, to other Afrotherian species, and to mammals generally, but certain differences in the nuclear complement highlighted phylogenetic interrelationships. The golden mole was observed to have cholinergic interneurons in the cerebral cortex, hippocampus, olfactory bulb and amygdala. The four-toed sengi had cholinergic neurons in both colliculi and in the cochlear nucleus, but lacked the catecholaminergic A15d group in the hypothalamus. In both the golden mole and the four-toed sengi, the locus coeruleus (A6d group) was made up of few neurons. The golden mole also exhibited an unusual foreshortening of the brain, such that a major (mesencephalic?) flexure in the brainstem was evident.
  Journal of chemical neuroanatomy 03/2013;
• Article: MAPPING OF TYROSINE HYDROXYLASE IN THE DIENCEPHALON OF ALPACA (LAMA PACOS) AND CO-DISTRIBUTION WITH SOMATOSTATIN-28 (1-12).

  P Marcos, M M Arroyo-Jiménez, G Lozano, J González-Fuentes, M J Lagartos-Donate, L A Aguilar, R Coveñas
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  ABSTRACT: Based on previous work describing the distribution of somatostatin-28 (1-12) in the male alpaca (Lama pacos) diencephalon, and owing to the well known interactions between this peptide and the catecholaminergic system, the aims of this work are: 1) to describe the distribution of putative catecholaminergic cell groups in the alpaca diencephalon and 2) to study the possible morphological basis of the interactions between these substances in the diencephalon of the alpaca by using double immunohistochemistry methods. Thus, the distribution of catecholaminergic cell groups in the alpaca diencephalon agrees with that previously described in the diencephalon of other mammalian species of the same order: the A11, A12, A13, A14 and A15d cell groups have been identified; however, we have observed an additional hitherto undescribed cell group containing tyrosine hydroxylase in the medial habenula. In addition, double-labelling procedures did not reveal neurons containing tyrosine hydroxylase and somatostatin, suggesting that the hypothalamic interactions between catecholamines and somatostatin at intra-cellular level must be carried out by a somatostatin molecule other than fragment (1-12). Otherwise, the overlapping distribution patterns of these substances would suggest some interconnections between groups of chemospecific neurons. These results could be the starting point for future studies on hypothalamic functions in alpacas, for example those concerning reproductive control, since other physiological studies have suggested that this species could have different regulatory mechanisms from other mammalian species. Our results support the Manger hypothesis that the same nuclear complement of neural systems exists in the brain of species of the same order.
  Journal of chemical neuroanatomy 03/2013;
• Article: JAK2 inhibition is neuroprotective and reduces astrogliosis after quinolinic acid striatal lesion in adult mice.

  Raffaela Silvestre Ignarro, André Schwambach Vieira, Cesar Renato Sartori, Francesco Langone, Fábio Rogério, Carlos Amilcar Parada
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  ABSTRACT: Quinolinic acid (QA) striatal lesion in rodents induces neuronal death, astrogliosis and migration of neuroblasts from subventricular zone to damaged striatum. These phenomena occur in some human neurodegenerative illnesses, but the underlying mechanisms are unknown. We investigated the effect of AG490, a Janus-kinase 2 (JAK2) inhibitor, on astrogliosis, neuronal loss and neurogenesis in the striatum of adult mice after unilateral infusion of QA (30nmol). Animals were given subcutaneous injections of AG490 (10mg/kg) or vehicle immediately after lesion and then once daily for six days. Brain sections were used for neuronal stereological quantification, immunohistochemical and Western Blotting analyses for GFAP and doublecortin, markers of astrocytes and neuroblasts, respectively. The total area of doublecortin-positive cells (ADPC) and the number of neurons (NN) in the lesioned (L) and contralateral (CL) sides were evaluated. Neurogenesis index (NI=ADPC(L)/ADPC(CL)) and neuronal ratio (NR=NN(L)/NN(CL)) were calculated. After QA administration, blotting for GFAP showed an ipsilateral decrease of 19% in AG490- vs vehicle-treated animals. NR was 25% higher in mice given AG490 vs controls given vehicle. NI showed a decrease of 21% in AG490- vs vehicle-treated mice. Our results indicate that JAK2 inhibition reduces QA lesion and suggest that astrogliosis may impair neuronal survival in this model.
  Journal of chemical neuroanatomy 02/2013;
• Article: Pattern of distribution of serotonergic fibers to the obitomedial and insular cortex in the rat.

  Stephanie B Linley, Walter B Hoover, Robert P Vertes
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  ABSTRACT: As is well recognized, serotonergic (5-HT) fibers distribute widely throughout the brain, including the cerebral cortex. Although some early reports described the 5-HT innervation of the prefrontal cortex (PFC) in rats, the focus was on sensorimotor regions and not on the 'limbic' PFC - or on the medial, orbital and insular cortices. In addition, no reports have described the distribution of 5-HT fibers to PFC in rats using antisera to the serotonin transporter (SERT). Using immunostaining for SERT, we examined the pattern of distribution of 5-HT fibers to the medial, orbital and insular cortices in the rat. We show that 5-HT fibers distribute massively throughout all divisions of the PFC, with distinct laminar variations. Specifically, 5-HT fibers were densely concentrated in superficial (layer 1) and deep (layers 5/6) of the PFC but less heavily so in intermediate layers (layers 2/3). This pattern was most pronounced in the orbital cortex, particularly in the ventral and ventrolateral orbital cortices. With the emergence of granular divisions of the insular cortex, the granular cell layer (layer 4) was readily identifiable by a dense band of labeling confined to it, separating layer 4 from less heavily labeled superficial and deep layers. The pattern of 5-HT innervation of medial, orbital and insular cortices significantly differed from that of sensorimotor regions of the PFC. Serotonergic labeling was much denser overall in limbic compared to non-limbic regions of the PFC, as was striking demonstrated by the generally weaker labeling in layers 1-3 of the primary sensory and motor cortices. The massive serotonergic innervation of the medial, orbital and insular divisions of the PFC likely contributes substantially to well established serotonergic effects on affective and cognitive functions, including a key role in many neurological and psychiatric diseases.
  Journal of chemical neuroanatomy 01/2013;
• Article: Adrenalectomy and corticosterone replacement differentially alter CA3 dendritic morphology and new cell survival in the adult rat hippocampus.

  M Martinez-Claros, H W Steinbusch, A van Selm, D L A van den Hove, J Prickaerts, J L Pawluski
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  ABSTRACT: Plastic changes in the adult mammal hippocampus can be altered by many factors and perhaps the most well-documented is stress. Stress and elevated corticosterone levels have been shown to decrease hippocampal neurogenesis and decrease the complexity of CA3 pyramidal neurons. However, the extent of these changes in relation to low and moderately elevated levels of corticosterone has yet to be fully investigated. Therefore, the aim of the present study was to determine how low to moderately elevated circulating corticosterone levels affect dendritic morphology of CA3 pyramidal cells and hippocampal neurogenesis in adult male rats. To do this, three groups of adult male Wistar rats were used: 1. Sham-operated, 2. Adrenalectomized (ADX), and 3. ADX+corticosterone replacement. Primary results show that adrenalectomy, but not moderately elevated levels of corticosterone replacement, resulted in significant atrophy of CA3 pyramidal neurons. Interestingly, moderate corticosterone replacement resulted in significantly more surviving new cells in the dentate gyrus when compared to sham controls. This work shows that circulating levels of corticosterone differentially affect plasticity in the CA3 region and the dentate gyrus.
  Journal of chemical neuroanatomy 01/2013;
• Article: Neurochemical profiling of dopaminergic neurons in the forebrain of a cichlid fish, Astatotilapia burtoni.

  Lauren A O'Connell, Miles R Fontenot, Hans A Hofmann
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  ABSTRACT: Across vertebrates, the mesolimbic reward system is a highly conserved neural network that serves to evaluate the salience of environmental stimuli, with dopamine as the neurotransmitter most relevant to its function. Although brain regions in the dopaminergic reward system have been well characterized in mammals, homologizing these brain areas with structures in teleosts has been controversial, especially for the mesencephalo-diencephalic dopaminergic cell populations. Here we examine the neurochemical profile of five dopaminergic cell groups (Vc, POA, PPr, TPp, pTn) in the model cichlid Astatotilapia burtoni to better understand putative homology relationships between teleosts and mammals. We characterized in the adult brain the expression patterns of three genes (etv5, nr4a2, and pitx3) that either specify dopaminergic cell fate or differentiate dopaminergic cell populations. We then determined whether these genes are expressed in dopaminergic cells. We find many striking similarities in these gene expression profiles between dopaminergic cell populations in teleosts and their putative mammalian homologs. Our results suggest that many of these dopaminergic cell groups are indeed evolutionarily ancient and conserved across vertebrates.
  Journal of chemical neuroanatomy 01/2013;
• Article: Dexamethasone induces different morphological changes in the dorsal and ventral hippocampus of rats.

  Adriana Berenice Silva-Gómez, Yuritze Aguilar-Salgado, Diego Octavio Reyes-Hernández, Gonzalo Flores
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  ABSTRACT: Dexamethasone (DEX), a synthetic glucocorticoid widely used in neurological illnesses because of its antiinflammatory properties, has many serious side effects, including severe psychiatric symptoms such as psychoses. The hippocampus is divided in the dorsal hippocampus (DH) and ventral hippocampus (VH) with each region having a subfield of CA1 and CA3 pyramidal layers. Great interest has recently emerged showing that the DH and VH are functionally different. In our work we determined whether, and what, changes occurred, after five days of DEX (0.2mg/kg) treatment, on the dendritic morphology of the CA1 and CA3 pyramidal neurons of the DH and VH of adult Sprague-Dawley rats. The dendritic morphology and characteristics were measured by using the Golgi-Cox procedure followed by a Sholl analysis. DEX decreased the number of dendritic spines of both apical and basolateral dendrites. Interestingly, this decrease was more pronounced in the VH. Only the VH neurons were affected by DEX with a decrease in their total dendritic length (TDL). An interesting point is that the VH neurons are longer that the DH neurons among the groups injected with saline only as the control. The length per branch order was only altered in the apical dendritic tree of the CA1 neurons. These data taken together show that the VH is more susceptible to DEX and its neurons are larger than the DH neurons. These results support previous observations related to differences between the DH and VH and suggest differences in the expression of the glucocorticoid receptors in connectivity and the space to elongate their dendritic arbor.
  Journal of chemical neuroanatomy 12/2012;
• Article: Critical role for PDE4 subfamilies in the development of experimental autoimmune encephalomyelitis.

  Cristina Sanabra, Emily M Johansson, Guadalupe Mengod
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  ABSTRACT: Experimental autoimmune encephalomyelitis (EAE) is an animal model of multiple sclerosis exhibiting neuroinflammation, axonal damage and demyelination, further characterized by T- and B-cell responses to myelin oligodendrocyte glycoprotein. Pharmacological manipulation of phosphodiesterases (PDEs) provokes profound anti-inflammatory responses through modulation of cAMP levels. The PDE4B subfamily has been related to the inflammatory immune response in mice and PDE4 inhibition produces amelioration of the clinical signs and delayed onset in the EAE model. Analyses of the expression of the mRNA coding for PDE4B splice variants revealed an upregulation of PDE4B2 in the brainstem and spinal cord of EAE mice which correlated with forkhead box P3 (FoxP3) and transforming growth factor beta (TGF-β) mRNAs expression in a score-dependent manner. The increase observed for the PDE4B protein was mainly found in antigen-presenting cells (APCs) such as dendritic cells and microglia/macrophages, in areas with high cellular infiltration. Unexpectedly, PDE4B(-/-) mice showed an earlier onset of the disease compared to wildtype mice. The results point to a possible role of the PDE4B enzyme and in particular the PDE4B2 splice variant during EAE pathogenesis, probably by modulating cAMP levels in APCs, consequently influencing the cytokine environment important for T-cell differentiation.
  Journal of chemical neuroanatomy 12/2012;
• Article: Differential maturation of GIRK2-expressing neurons in the mouse cerebellum.

  Carolina Aguado, Laura Fernández-Alacid, María José Cabañero, Yuchio Yanagawa, Karl Schilling, Masahiko Watanabe, Jean-Marc Fritschy, Rafael Luján
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  ABSTRACT: The cerebellar cortex is among the brain regions showing the highest expression levels of G-protein-gated inwardly-rectifying potassium (GIRK/Kir3) channels. Despite their critical contribution in modulating neuronal excitability during development and adult, the spatiotemporal expression of specific GIRK subunits in identified cerebellar neuron populations is unresolved. To characterize this onset of expression, we examined the GIRK2 protein expression in mouse cerebellum by western blot, light microscopy immunohistochemistry and immunofluorescence during perinatal development. Using western blots, GIRK2 expression was low at birth but reach its maximum at P5 before decreasing gradually to adult levels. Immunohistochemical localization indicated that GIRK2 is expressed in granule cells from early stages of development. At the embryonic stage, immunofluorescence techniques for the transcription factor Pax6 allowed to demonstrate that GIRK2 is expressed in granule cell precursors. This GIRK2 expression in granule cells continued throughout postnatal development and adulthood. In addition, the expression of Pax2-GFP allowed selective visualization of Golgi cells during pre- and postnatal development. We could not detect co-expression of Pax2-GFP and GIRK2 during prenatal and early postnatal development, but only at post-migratory stages of Golgi cells, once they are morphologically differentiated and located at the granule cell layer. In the adult cerebellum, we performed a detailed characterization on the expression of GIRK2 in different subpopulations of Golgi cells, using metabotropic glutamate receptor 2 (mGlu(2)) and neurogranin as markers, in GlyT2-GFP and GAD67-GFP mice, and showed that GIRK2 is present in at least four morphological and neurochemical non-overlapping populations of Golgi cells. Altogether, these findings shed new light on the developmental regulation of GIRK channels in the cerebellum, and the main expression in granule cells during perinatal development support the idea that GIRK2 may provide a significant route for modulating different aspects of cerebellar development.
  Journal of chemical neuroanatomy 12/2012;
• Article: Acute hypoxia-induced depletion of striatal nitric oxide synthase pathway.

  Francisco Molina, Alma Rus, Juan Ángel Pedrosa, Ma Luisa Del Moral
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  ABSTRACT: Hypoxia-induced alteration of nitric oxide (NO) production may lead to brain disease, especially in the areas most sensitive to oxygen deficiency, such as the striatum. To date, the behaviour of the striatal NO pathway under hypoxia/reoxygenation remains unknown and its elucidation constitutes the aim of this work. Wistar rats were submitted to hypoxia (20min) and analysed after 0h, 24h, and 5 days of reoxygenation. Expression, activity, and location of the NO synthase (NOS) isoforms (neuronal, endothelial, and inducible) as well as nitrated protein expression were analyzed in the rat striatum. NO levels were indirectly quantified as nitrates and nitrites (NOx), which act as NO-generating molecules. NOS isoform mRNA levels remained unaltered in hypoxic groups vs. normoxic control. However, quantification of immunoreaction showed a significant decrease in eNOS and nNOS after hypoxia. While in situ NOS activity and NOx levels fell, levels of nitrotyrosine-modified proteins rose throughout the reoxygenation period. Our data revealed the great complexity of the NO pathway, showing that both acute hypoxia and the successive recovery period down-regulated the NOS system in the rat striatum. However, under hypoxia/reoxygenation NO may be produced in a NOS-independent way from the NO-storage molecules, compensating for the hypoxia-reduced NOS activity.
  Journal of chemical neuroanatomy 12/2012;