scholarly journals Inverse Density of Iba1 and Glutamine Synthetase Expressing Glia in Rat Inferior Colliculus

2021 ◽  
Author(s):  
Llwyd David Orton
Keyword(s):  
Glial Cell ◽  
Calcium Binding ◽  
Cell Types ◽  
Central Nucleus ◽  
Gradual Transition ◽  
Relative Distribution ◽  
Dorsal Cortex ◽  
Auditory Midbrain ◽  
Cellular Density ◽  
Male Wistar Rats

Microglia and astrocytes undertake numerous essential roles in nervous systems but we know little of their anatomical distribution within numerous nuclei. In the principal nuclei of the mammalian auditory midbrain, the inferior colliculi (IC), the cellular density and relative distribution of glutamate synthetase (GS) expressing astrocytes and ionized calcium-binding adapter molecule 1 (Iba1) expressing microglia is unknown. To address this, the IC of young adult, male Wistar rats were immunohistochemically labelled for GS and Iba1, using chromogenic methods. Sub-regions of imaged IC sections were demarked and soma density of both cell types determined. GS labelled somata were twice more densely packed as Iba1 labelled somata throughout IC parenchyma and peri-vascular regions. Furthermore, GS labelled somata density was significantly lower in dorsal cortex than external cortex or central nucleus. Iba1 labelled somata density exhibited the opposite trend, revealing an inverse density of these glial cell types between IC sub-regions. GS labelled neuropil was strongest in the cortices with and a gradual transition of lighter labelling towards central nucleus. These data provide the first detailed descriptions of GS labelling in IC and demonstrate sub-regional differences in IC glial cell density. Taken together, these findings suggest neurochemical specialization of glia in IC sub-regions, likely related to local physiological and metabolic demands, with implications for IC function.

scholarly journals Unifying the Midbrain

2018 ◽  
pp. 548-576
Author(s):  
Adrian Rees ◽  
Llwyd D. Orton
Keyword(s):  
Inferior Colliculus ◽  
Auditory Processing ◽  
Auditory Pathway ◽  
Neural Representation ◽  
Central Nucleus ◽  
Dorsal Cortex ◽  
Auditory Midbrain ◽  
Inferior Colliculi ◽  
Behavioral Influences

Commissural fibres interconnecting the two sides of the brain are found at several points along the auditory pathway, thus suggesting their fundamental importance for the analysis of sound. This chapter presents an overview of what is currently known about the anatomy, physiology, and behavioral influences of the commissure of the inferior colliculus (CoIC)—the most prominent brainstem auditory commissure—that reciprocally interconnects the principal nuclei of the auditory midbrain, the inferior colliculi (IC). The primary contribution to the CoIC originates from neurons projecting from one inferior colliculus to the other, with the dorsal cortex and central nucleus providing the most extensive connections. In addition, many ascending and descending auditory centers send projections to the IC via the CoIC, together with diverse sources located outside the classically defined auditory pathway. The degree of interconnection between the two ICs suggests they function as a single entity. Recent in vivo evidence has established that CoIC projections modulate the neural representation of sound frequency, level, and location in the IC, thus indicating an important role for the CoIC in auditory processing. However, there is limited evidence for the influence of the CoIC on auditory behavior. This, together with the diversity of sources projecting via the CoIC, suggest unknown roles that warrant further exploration.

Duration Selective Neurons in the Inferior Colliculus of the Rat: Topographic Distribution and Relation of Duration Sensitivity to Other Response Properties

2006 ◽  
Vol 95 (2) ◽  
pp. 823-836 ◽  
Author(s):  
D. Pérez-González ◽  
M. S. Malmierca ◽  
J. M. Moore ◽  
O. Hernández ◽  
E. Covey
Keyword(s):  
Inferior Colliculus ◽  
Excitatory Input ◽  
Central Nucleus ◽  
Response Patterns ◽  
Dorsal Cortex ◽  
Auditory Midbrain ◽  
Duration Threshold ◽  
Band Pass ◽  
Species Specific ◽  
Sound Duration

Many animals use duration to help them identify the source and meaning of a sound. Duration-sensitive neurons have been found in the auditory midbrain of mammals and amphibians, where their selectivity seems to correspond to the lengths of species-specific vocalizations. In this study, single neurons in the rat inferior colliculus (IC) were tested for sensitivity to sound duration. About one-half (54%) of the units sampled showed some form of duration selectivity. The majority of these (76%) were long-pass neurons that responded to sounds exceeding some duration threshold (range: 5–60 ms). Band-pass neurons, which only responded to a restricted range of durations, made up 13% of duration-sensitive neurons (best durations: 15–120 ms). Other units displayed short-pass (2%) or mixed (9%) response patterns. The majority of duration-sensitive neurons were localized outside the central nucleus of the IC, especially in the dorsal cortex, where more than one-half of the neurons sampled had long-pass selectivity for duration. Band-pass duration tuned neurons were only found outside the central nucleus. Characteristics of duration-sensitive neurons in the rat support the idea that this filtering arises through an interaction of excitatory and inhibitory inputs that converge in the IC. Band-pass neurons typically responded at sound offset, suggesting that their tuning is created through the same mechanisms that have been described in echolocating bats. The finding that the first-spike latencies of all long-pass neurons were longer than the shortest duration to which they responded supports the idea that they receive transient inhibition before, or simultaneously with, a sustained excitatory input. The ranges of selectivity in rat IC neurons are within the range of durations of rat vocalizations. These data suggest that a population of neurons in the rat IC have evolved to transmit information about behaviorally relevant sound durations using mechanisms that are common to all mammals, with an emphasis on long-pass tuning characteristics.

scholarly journals Thyroid Hormone Action in Cerebellum and Cerebral Cortex Development

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Fabrice Chatonnet ◽  
Frédéric Picou ◽  
Teddy Fauquier ◽  
Frédéric Flamant
Keyword(s):  
Cerebral Cortex ◽  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Glial Cell ◽  
Nuclear Receptors ◽  
Target Genes ◽  
Cell Types ◽  
Hormone Action ◽  
Cerebral Cortex Development ◽  
Thyroid Hormone Action

Thyroid hormones (TH, including the prohormone thyroxine (T4) and its active deiodinated derivative 3,,5-triiodo-L-thyronine (T3)) are important regulators of vertebrates neurodevelopment. Specific transporters and deiodinases are required to ensure T3 access to the developing brain. T3 activates a number of differentiation processes in neuronal and glial cell types by binding to nuclear receptors, acting directly on transcription. Only few T3 target genes are currently known. Deeper investigations are urgently needed, considering that some chemicals present in food are believed to interfere with T3 signaling with putative neurotoxic consequences.

Phase-Locked Responses to Pure Tones in the Inferior Colliculus

2006 ◽  
Vol 95 (3) ◽  
pp. 1926-1935 ◽  
Author(s):  
Liang-Fa Liu ◽  
Alan R. Palmer ◽  
Mark N. Wallace
Keyword(s):  
Guinea Pig ◽  
Inferior Colliculus ◽  
Phase Locking ◽  
Single Units ◽  
Central Nucleus ◽  
Dorsal Cortex ◽  
Upper Limits ◽  
Ascending Pathways ◽  
Pure Tones ◽  
The Brain

In the auditory system, some ascending pathways preserve the precise timing information present in a temporal code of frequency. This can be measured by studying responses that are phase-locked to the stimulus waveform. At each stage along a pathway, there is a reduction in the upper frequency limit of the phase-locking and an increase in the steady-state latency. In the guinea pig, phase-locked responses to pure tones have been described at various levels from auditory nerve to neocortex but not in the inferior colliculus (IC). Therefore we made recordings from 161 single units in guinea pig IC. Of these single units, 68% (110/161) showed phase-locked responses. Cells that phase-locked were mainly located in the central nucleus but also occurred in the dorsal cortex and external nucleus. The upper limiting frequency of phase-locking varied greatly between units (80−1,034 Hz) and between anatomical divisions. The upper limits in the three divisions were central nucleus, >1,000 Hz; dorsal cortex, 700 Hz; external nucleus, 320 Hz. The mean latencies also varied and were central nucleus, 8.2 ± 2.8 (SD) ms; dorsal cortex, 17.2 ms; external nucleus, 13.3 ms. We conclude that many cells in the central nucleus receive direct inputs from the brain stem, whereas cells in the external and dorsal divisions receive input from other structures that may include the forebrain.

scholarly journals Centrin2 regulates CP110 removal in primary cilium formation

2015 ◽  
Vol 208 (6) ◽  
pp. 693-701 ◽  
Author(s):  
Suzanna L. Prosser ◽  
Ciaran G. Morrison
Keyword(s):  
Calcium Binding ◽  
Primary Cilia ◽  
Reverse Genetics ◽  
Cell Types ◽  
Serum Starvation ◽  
Basal Bodies ◽  
Cilium Formation ◽  
Cellular Quiescence ◽  
Retinal Pigmented Epithelial Cells

Primary cilia are antenna-like sensory microtubule structures that extend from basal bodies, plasma membrane–docked mother centrioles. Cellular quiescence potentiates ciliogenesis, but the regulation of basal body formation is not fully understood. We used reverse genetics to test the role of the small calcium-binding protein, centrin2, in ciliogenesis. Primary cilia arise in most cell types but have not been described in lymphocytes. We show here that serum starvation of transformed, cultured B and T cells caused primary ciliogenesis. Efficient ciliogenesis in chicken DT40 B lymphocytes required centrin2. We disrupted CETN2 in human retinal pigmented epithelial cells, and despite having intact centrioles, they were unable to make cilia upon serum starvation, showing abnormal localization of distal appendage proteins and failing to remove the ciliation inhibitor CP110. Knockdown of CP110 rescued ciliation in CETN2-deficient cells. Thus, centrin2 regulates primary ciliogenesis through controlling CP110 levels.

scholarly journals Identification of the glial cell types containing carnosine-related peptides in the rat brain

1997 ◽  
Vol 237 (1) ◽  
pp. 37-40 ◽  
Author(s):  
Silvia De Marchis ◽  
Roberto Cosimo Melcangi ◽  
Chiara Modena ◽  
Ilaria Cavaretta ◽  
Paolo Peretto ◽  
...  
Keyword(s):  
Rat Brain ◽  
Glial Cell ◽  
Cell Types

scholarly journals Conformational epitopes at cadherin calcium-binding sites and p120-catenin phosphorylation regulate cell adhesion

2012 ◽  
Vol 23 (11) ◽  
pp. 2092-2108 ◽  
Author(s):  
Yuliya I. Petrova ◽  
MarthaJoy M. Spano ◽  
Barry M. Gumbiner
Keyword(s):  
Cell Surface ◽  
Conformational Changes ◽  
Binding Sites ◽  
Calcium Binding ◽  
Cell Types ◽  
P120 Catenin ◽  
Physiological Regulation ◽  
Conformational Epitopes ◽  
Calcium Binding Sites ◽  
E Cadherin

We investigated changes in cadherin structure at the cell surface that regulate its adhesive activity. Colo 205 cells are nonadhesive cells with a full but inactive complement of E-cadherin–catenin complexes at the cell surface, but they can be triggered to adhere and form monolayers. We were able to distinguish the inactive and active states of E-cadherin at the cell surface by using a special set of monoclonal antibodies (mAbs). Another set of mAbs binds E-cadherin and strongly activates adhesion. In other epithelial cell types these activating mAbs inhibit growth factor–induced down-regulation of adhesion and epithelial morphogenesis, indicating that these phenomena are also controlled by E-cadherin activity at the cell surface. Both types of mAbs recognize conformational epitopes at different interfaces between extracellular cadherin repeat domains (ECs), especially near calcium-binding sites. Activation also induces p120-catenin dephosphorylation, as well as changes in the cadherin cytoplasmic domain. Moreover, phospho-site mutations indicate that dephosphorylation of specific Ser/Thr residues in the N-terminal domain of p120-catenin mediate adhesion activation. Thus physiological regulation of the adhesive state of E-cadherin involves physical and/or conformational changes in the EC interface regions of the ectodomain at the cell surface that are mediated by catenin-associated changes across the membrane.

Sleep Deprivation Induces Neuroinflammation and Depressive-like Behaviors by Impairing the Regulation of Circadian Clock Genes Expression in Rats

2020 ◽  
Author(s):  
Chen Xing ◽  
Yanzhao Zhou ◽  
Huan Xu ◽  
Mengnan Ding ◽  
Yifan Zhang ◽  
...  
Keyword(s):  
Sleep Deprivation ◽  
Circadian Clock ◽  
Glial Cell ◽  
Hpa Axis ◽  
Calcium Binding ◽  
Cell Activation ◽  
Clock Genes ◽  
Sleep Loss ◽  
Genes Expression ◽  
Circadian Clock Genes

Abstract Background: Sleep loss leads to a spectrum of mood disorders such as anxiety, cognitive dysfunction and motor coordination impairment in many individuals. However, the underlying mechanisms are largely unknown. Methods: In this study, we examined the effects of sleep deprivation (SD) on depression and the mechanism by subjecting rats to a slowly rotating platform for 3 days to mimic the process of sleep loss. Sleep-deprived animals were tested behaviorally for anxiety- and depressive-like behaviors. We further studied the effects of SD on hypothalamic-pituitary-adrenal (HPA) axis activity, and at the end of the experiment, brains were collected to measure the circadian clock genes expression in the hypothalamus, glial cell activation and inflammatory cytokine alterations. Results: Our results indicated that SD for 3 days resulted in anxiety- and depressive-like behaviors. SD exaggerated cortisol response to HPA axis, significantly altered the mRNA profile of circadian clock genes, and induced neuroinflammation by increasing the expression of glial cell markers, including the microglial marker ionized calcium-binding adapter molecule 1 (Iba1) and the astroglial marker glial fibrillary acidic protein (GFAP). The expression of M1 and M2 microglial markers (Arg-1 and CD206, respectively) and pro-inflammatory cytokines (IL-1β, IL-6 and TNF-α) were increased in the brain. Conclusion: These results indicated that SD for 3 days induced anxiety- and depression-like behaviors in rats by impairing the regulation of circadian clock genes and inducing neuroinflammation, ultimately resulting in brain injury.

scholarly journals Prevalent presence of periodic actin–spectrin-based membrane skeleton in a broad range of neuronal cell types and animal species

2016 ◽  
Vol 113 (21) ◽  
pp. 6029-6034 ◽  
Author(s):  
Jiang He ◽  
Ruobo Zhou ◽  
Zhuhao Wu ◽  
Monica A. Carrasco ◽  
Peri T. Kurshan ◽  
...  
Keyword(s):  
Glial Cell ◽  
Animal Species ◽  
Homo Sapiens ◽  
Neuronal Cell ◽  
Cell Types ◽  
Membrane Skeleton ◽  
Brain Regions ◽  
Inhibitory Neurons ◽  
Periodic Distribution ◽  
Neuronal Types

Actin, spectrin, and associated molecules form a periodic, submembrane cytoskeleton in the axons of neurons. For a better understanding of this membrane-associated periodic skeleton (MPS), it is important to address how prevalent this structure is in different neuronal types, different subcellular compartments, and across different animal species. Here, we investigated the organization of spectrin in a variety of neuronal- and glial-cell types. We observed the presence of MPS in all of the tested neuronal types cultured from mouse central and peripheral nervous systems, including excitatory and inhibitory neurons from several brain regions, as well as sensory and motor neurons. Quantitative analyses show that MPS is preferentially formed in axons in all neuronal types tested here: Spectrin shows a long-range, periodic distribution throughout all axons but appears periodic only in a small fraction of dendrites, typically in the form of isolated patches in subregions of these dendrites. As in dendrites, we also observed patches of periodic spectrin structures in a small fraction of glial-cell processes in four types of glial cells cultured from rodent tissues. Interestingly, despite its strong presence in the axonal shaft, MPS is disrupted in most presynaptic boutons but is present in an appreciable fraction of dendritic spine necks, including some projecting from dendrites where such a periodic structure is not observed in the shaft. Finally, we found that spectrin is capable of adopting a similar periodic organization in neurons of a variety of animal species, including Caenorhabditis elegans, Drosophila, Gallus gallus, Mus musculus, and Homo sapiens.

Genetic analyses uncover pleiotropic compensatory roles for Drosophila Nucleobindin-1 in inositol trisphosphate-mediated intracellular calcium homeostasis

Genome ◽  
2020 ◽  
Vol 63 (2) ◽  
pp. 61-90
Author(s):  
Vidhya Balasubramanian ◽  
Bharath Srinivasan
Keyword(s):  
Intracellular Calcium ◽  
Calcium Binding ◽  
Model Organism ◽  
Cell Types ◽  
Single Copy ◽  
Structural Determinants ◽  
Α Subunit ◽  
Behavioral Abnormalities ◽  
Mutant Phenotypes ◽  
Trisphosphate Receptor

Nucleobindin-1 is an EF-hand calcium-binding protein with a distinctive profile, predominantly localized to the Golgi in insect and wide-ranging vertebrate cell types, alike. Its putative involvements in intracellular calcium (Ca2+) homeostasis have never been phenotypically characterized in any model organism. We have analyzed an adult-viable mutant that completely disrupts the G protein α-subunit binding and activating (GBA) motif of Drosophila Nucleobindin-1 (dmNUCB1). Such disruption does not manifest any obvious fitness-related, morphological/developmental, or behavioral abnormalities. A single copy of this mutation or the knockdown of dmnucb1 in restricted sets of cells variously rescues pleiotropic mutant phenotypes arising from impaired inositol 1,4,5-trisphosphate receptor (IP3R) activity (in turn depleting cytoplasmic Ca2+ levels across diverse tissue types). Additionally, altered dmNUCB1 expression or function considerably reverses lifespan and mobility improvements effected by IP3R mutants, in a Drosophila model of amyotrophic lateral sclerosis. Homology modeling-based analyses further predict a high degree of conformational conservation in Drosophila, of biochemically validated structural determinants in the GBA motif that specify in vertebrates, the unconventional Ca2+-regulated interaction of NUCB1 with Gαi subunits. The broad implications of our findings are hypothetically discussed, regarding potential roles for NUCB1 in GBA-mediated, Golgi-associated Ca2+ signaling, in health and disease.

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