Instituto Cajal

Madrid, Spain

Instituto Cajal

Madrid, Spain
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Methamphetamine (METH), a commonly abused psychostimulant, causes dopamine neurotoxicity in humans, rodents, and nonhuman primates. This study examined the selective neuroanatomical pattern of dopaminergic neurotoxicity induced by METH in the mouse striatum. We examined the effect of METH on tyrosine hydroxylase (TH) and dopamine transporter (DAT) immunoreactivity in the different compartments of the striatum and in the nucleus accumbens. The levels of dopamine and its metabolites, 3,4-dihidroxyphenylacetic acid and homovanillic acid, as well as serotonin (5-HT) and its metabolite, 5-hydroxyindolacetic acid, were also quantified in the striatum. Mice were given three injections of METH (4 mg/kg, i.p.) at 3 h intervals and sacrificed 7 days later. This repeated METH injection induced a hyperthermic response and a decrease in striatal concentrations of dopamine and its metabolites without affecting 5-HT concentrations. In addition, the drug caused a reduction in TH- and DAT-immunoreactivity when compared to saline-treated animals. Interestingly, there was a significantly greater loss of TH- and DAT-immunoreactivity in striosomes than in the matrix. The predominant loss of dopaminergic terminals in the striosomes occurred along the rostrocaudal axis of the striatum. In contrast, METH did not decrease TH- or DAT-immunoreactivity in the nucleus accumbens. These results provide the first evidence that compartments of the mouse striatum, striosomes and matrix, and mesolimbic and nigrostriatal pathways have different vulnerability to METH. This pattern is similar to that observed with other neurotoxins such as MPTP, the most widely used model of Parkinson's disease, in early Huntington's disease and hypoxic/ischemic injury, suggesting that these conditions might share mechanisms of neurotoxicity.

Garcia-Marques J.,Instituto Cajal | Nunez-Llaves R.,Instituto Cajal | Lopez-Mascaraque L.,Instituto Cajal
Journal of Neuroscience | Year: 2014

NG2-glia are the most unknown population originating in the CNS. Despite their relative abundance in the brain, fundamental questions about their function, heterogeneity, and origin remain in debate. Particularly, it is still intriguing how these cells escaped from classical in vivo clonal analyses describing other neural types. Using StarTrack labeling in mouse brains, we found that NG2-glia are produced as immense clonal clusters whose number of cells is about one order of magnitude higher than in other neural types. Unexpectedly, this number remained low during embryonic and early postnatal stages, increasing during adulthood. In addition, we also demonstrated a pallial origin of a telencephalic NG2 population, which in the olfactory bulb is derived from local progenitors. Together, our results reveal an original ontogenic process that gives rise to the NG2-glia population and expands the previously established limits of development. © 2014 the authors.

Perea G.,Instituto Cajal | Sur M.,Massachusetts Institute of Technology | Araque A.,University of Minnesota
Frontiers in Cellular Neuroscience | Year: 2014

Astrocytes, the most abundant glial cell in the brain, play critical roles in metabolic and homeostatic functions of the Nervous System; however, their participation in coding information and cognitive processes has been largely ignored. The strategic position of astrocyte processes facing synapses and the astrocyte ability to uptake neurotransmitters and release neuroactive substances, so-called “gliotransmitters”, provide the scenario for prolific neuron-astrocyte signaling. From studies at single-cell level to animal behavior, recent advances in technology and genetics have revealed the impact of astrocyte activity in brain function from cellular and synaptic physiology, neuronal circuits to behavior. The present review critically discusses the consequences of astrocyte signaling on synapses and networks, as well as its impact on neuronal information processing, showing that some crucial brain functions arise from the coordinated activity of neuron-glia networks. © 2014 Perea, Sur and Araque.

Melcangi R.C.,University of Milan | Giatti S.,University of Milan | Garcia-Segura L.M.,Instituto Cajal
Neuroscience and Biobehavioral Reviews | Year: 2016

Neuroactive steroids regulate the physiology of the central and peripheral nervous system, exert neuroprotective actions and represent interesting tools for therapeutic strategies against neurodegenerative and psychiatric disorders. Sex differences in their levels are detected not only under physiological conditions but are also modified in a sex-dependent way in different pathological alterations such as Alzheimer's disease, Parkinson's disease, Huntington's disease, multiple sclerosis, traumatic brain injury, spinal cord injury, stroke, diabetic encephalopathy, psychiatric disorders and peripheral neuropathy. Interestingly, many of these disorders show sex differences in their incidence, symptomatology and/or neurodegenerative outcome. The neuroprotective actions of neuroactive steroids, together with the sex specific regulation of its levels might provide the basis to design sex-specific neuroprotective therapies. Indeed, some experiments here discussed suggest the viability of this approach. © 2015 Elsevier Ltd

Arevalo M.-A.,Instituto Cajal | Azcoitia I.,Complutense University of Madrid | Garcia-Segura L.M.,Instituto Cajal
Nature Reviews Neuroscience | Year: 2015

Hormones regulate homeostasis by communicating through the bloodstream to the body's organs, including the brain. As homeostatic regulators of brain function, some hormones exert neuroprotective actions. This is the case for the ovarian hormone 17β-oestradiol, which signals through oestrogen receptors (ERs) that are widely distributed in the male and female brain. Recent discoveries have shown that oestradiol is not only a reproductive hormone but also a brain-derived neuroprotective factor in males and females and that ERs coordinate multiple signalling mechanisms that protect the brain from neurodegenerative diseases, affective disorders and cognitive decline. © 2014 Macmillan Publishers Limited. All rights reserved.

Dendritic spines receive the majority of excitatory connections in the central nervous system, and, thus, they are key structures in the regulation of neural activity. Hence, the cellular and molecular mechanisms underlying their generation and plasticity, both during development and in adulthood, are a matter of fundamental and practical interest. Indeed, a better understanding of these mechanisms should provide clues to the development of novel clinical therapies. Here, we present original results obtained from high-quality images of Cajal's histological preparations, stored at the Cajal Museum (Instituto Cajal, CSIC), obtained using extended focus imaging, three-dimensional reconstruction, and rendering. Based on the data available in the literature regarding the formation of dendritic spines during development and our results, we propose a unifying model for dendritic spine development.

Wu J.,Mount Sinai School of Medicine | Roman A.-C.,Instituto Cajal | Carvajal-Gonzalez J.M.,Mount Sinai School of Medicine | Mlodzik M.,Mount Sinai School of Medicine
Nature Cell Biology | Year: 2013

Planar cell polarity (PCP) is cellular polarity within the plane of an epithelial tissue or organ. PCP is established through interactions of the core Frizzled (Fz)/PCP factors and, although their molecular interactions are beginning to be understood, the upstream input providing the directional bias and polarity axis remains unknown. Among core PCP genes, Fz is unique as it regulates PCP both cell-autonomously and non-autonomously, with its extracellular domain acting as a ligand for Van Gogh (Vang). We demonstrate in Drosophila melanogaster wings that Wg (Wingless) and dWnt4 (Drosophila Wnt homologue) provide instructive regulatory input for PCP axis determination, establishing polarity axes along their graded distribution and perpendicular to their expression domain borders. Loss-of-function studies reveal that Wg and dWnt4 act redundantly in PCP determination. They affect PCP by modulating the intercellular interaction between Fz and Vang, which is thought to be a key step in setting up initial polarity, thus providing directionality to the PCP process. © 2013 Macmillan Publishers Limited. All rights reserved.

Navarrete M.,Instituto Cajal | Araque A.,Instituto Cajal
Neuron | Year: 2010

Endocannabinoids and their receptor CB1 play key roles in brain function. Astrocytes express CB1Rs that are activated by endocannabinoids released by neurons. However, the consequences of the endocannabinoid-mediated neuron-astrocyte signaling on synaptic transmission are unknown. We show that endocannabinoids released by hippocampal pyramidal neurons increase the probability of transmitter release at CA3-CA1 synapses. This synaptic potentiation is due to CB1R-induced Ca2+ elevations in astrocytes, which stimulate the release of glutamate that activates presynaptic metabotropic glutamate receptors. While endocannabinoids induce synaptic depression in the stimulated neuron by direct activation of presynaptic CB1Rs, they indirectly lead to synaptic potentiation in relatively more distant neurons by activation of CB1Rs in astrocytes. Hence, astrocyte calcium signal evoked by endogenous stimuli (neuron-released endocannabinoids) modulates synaptic transmission. Therefore, astrocytes respond to endocannabinoids that then potentiate synaptic transmission, indicating that astrocytes are actively involved in brain physiology. © 2010 Elsevier Inc.

Perea G.,Instituto Cajal | Araque A.,Instituto Cajal
Brain Research Reviews | Year: 2010

The classical view of glial cells as simple supportive cells for neurons is being replaced by a new vision in which glial cells are active elements involved in the physiology of the nervous system. This new vision is based on the fact that astrocytes, a subtype of glial cells in the CNS, are stimulated by synaptically released neurotransmitters, which increase the astrocyte Ca2+ levels and stimulate the release of gliotransmitters that regulate synaptic efficacy and plasticity. Consequently, our understanding of synaptic function, previously thought to exclusively result from signaling between neurons, has also changed to include the bidirectional signaling between neurons and astrocytes. Hence, astrocytes have been revealed as integral elements involved in the synaptic physiology, therefore contributing to the processing, transfer and storage of information by the nervous system. Reciprocal communication between astrocytes and neurons is therefore part of the intercellular signaling processes involved in brain function. © 2009 Elsevier B.V.

Navarrete M.,Instituto Cajal | Araque A.,Instituto Cajal
Cell | Year: 2011

In this issue, Panatier et al. (2011) show that astrocytes detect synaptic activity induced by single action potentials and upregulate basal synaptic transmission through calcium-dependent mechanisms and purinergic signaling. These results demonstrate the relevance of astrocyte calcium in neurophysiology and confirm that astrocytes are actively involved in synaptic function. © 2011 Elsevier Inc.

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