Immunocytochemical analyses of astrocyte development in the olfactory bulb

Chiu, K.; Greer, Charles A.

doi:10.1016/0165-3806(96)00055-7

Cited by 43 publications

(35 citation statements)

References 27 publications

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“…In rats GFAP immunoreactivity was found distributed across all layers (Chiu & Greer, 1996) similar to what was observed in mice in the present study. On the other hand, GFAP is a marker of astrocytes and published studies about the effect of rabies on astroglia are scarce; research has focused mainly on neurons, because viral particles have only been found sporadically within the glial cells.…”

Section: Effect Of Rabies Infection On Gfap Expressionsupporting

confidence: 77%

Entry of Rabies Virus in the Olfactory Bulb of Mice and Effect of Infection on Cell Markers of Neurons and Astrocytes

Torres‐Fernández¹,

Daza²,

Santamaría-Romero³

et al. 2018

Int. J. Morphol.

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SUMMARY:There are few studies of infection by rabies virus in the olfactory bulb (OB). This work was carried out with the purpose of establishing the time required to detect rabies antigens in the OB of mouse, after the intramuscular inoculation of the virus and to evaluate the effect of the infection on the expression of three proteins: calbindin (CB), parvalbumin (PV) and the glial fibrillary acidic protein (GFAP). Mice were inoculated with rabies virus intramuscularly in the hind limbs. Every 8 hours, after 72 hours postinoculation (p.i.), animals were sacrificed by perfusion with paraformaldehyde and coronal sections of OB were obtained for immunohistochemical study. These cuts were used to reveal the entry and spread of viral antigens. Tissue sections obtained in the terminal phase of the disease (144 hours p.i.), and controls of the same age were also processed for immunohistochemistry of CB, PV and GFAP. Rabies virus antigens were initially detected at 80 hours p.i. in a few mitral cells. At 88 hours p.i. the antigens had spread through most of these neurons but until the terminal phase of the disease there was little dispersion of the virus towards other cellular layers of the OB. The CB protein was expressed in cells of the glomerular stratum, the PV in cells of the outer plexiform layer and the GFAP was expressed in all the layers of the OB. Viral infection generated loss of CB expression and increase of PV expression. Immunoreactivity to GFAP was increased in the outer plexiform layer of the OB as a response to infection.

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Section: Effect Of Rabies Infection On Gfap Expressionsupporting

confidence: 77%

Entry of Rabies Virus in the Olfactory Bulb of Mice and Effect of Infection on Cell Markers of Neurons and Astrocytes

Torres‐Fernández¹,

Daza²,

Santamaría-Romero³

et al. 2018

Int. J. Morphol.

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“…In the GL, GJC between astrocytes is preferentially confined within OG and thus overlaps neuronal organization. This feature results from at least two astroglial properties: (i) the oriented morphology of glomerular astrocytes processes toward the OG center (7)(8)(9) where most of the GL neuronal transmission occurs, and (ii) the enriched expression of the two astroglial Cxs within functional units, as already reported in the somatosensory cortex (25). In addition, the physical barrier formed by the somata of the juxtaglomerular neurons can also contribute to the gap in Cx expression observed around glomeruli (Fig.…”

Section: Discussionmentioning

confidence: 64%

“…The goal of this study is to determine how Cx-mediated intercellular communication in astrocytes is organized and modulated in this brain structure characterized by functional units. Features of OG astrocytes studied so far include their morphology (7,8), membrane currents (9, 10), and contribution to hemodynamic responses (11-13). Here, we report that in the glomerular layer (GL), astroglial morphologies and Cx expression patterns lead to a gap junctional communication (GJC) favored within individual OG.…”

mentioning

confidence: 99%

Plasticity of astroglial networks in olfactory glomeruli

Roux

Benchenane

Rothstein

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

119

118

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Several recent findings have shown that neurons as well as astrocytes are organized into networks. Indeed, astrocytes are interconnected through connexin-formed gap junction channels allowing exchanges of ions and signaling molecules. The aim of this study is to characterize astrocyte network properties in mouse olfactory glomeruli where neuronal connectivity is highly ordered. Dyecoupling experiments performed in olfactory bulb acute slices (P16-P22) highlight a preferential communication between astrocytes within glomeruli and not between astrocytes in adjacent glomeruli. Such organization relies on the oriented morphology of glomerular astrocytes to the glomerulus center and the enriched expression of two astroglial connexins (Cx43 and Cx30) within the glomeruli. Glomerular astrocytes detect neuronal activity showing membrane potential fluctuations correlated with glomerular local field potentials. Accordingly, gap junctional coupling of glomerular networks is reduced when neuronal activity is silenced by TTX treatment or after early sensory deprivation. Such modulation is lost in Cx30 but not in Cx43 KO mice, indicating that Cx30-formed channels are the molecular targets of this activity-dependent modulation. Extracellular potassium is a key player in this neuroglial interaction, because (i) the inhibition of dye coupling observed in the presence of TTX or after sensory deprivation is restored by increasing [K + ] e and (ii) treatment with a K ir channel blocker inhibits dye spread between glomerular astrocytes. Together, these results demonstrate that extracellular potassium generated by neuronal activity modulates Cx30-mediated gap junctional communication between glomerular astrocytes, indicating that strong neuroglial interactions take place at this first relay of olfactory information processing.O lfactory glomeruli (OG) represent functional units where olfactory signals are first processed (1, 2). The combination of the anatomical organization and the functional activity results in a highly ordered spatial map of glomerular activation associated with each odor (3, 4). However, this well-described organization refers only to neuronal circuits, and information concerning astroglial connectivity is lacking. In the brain, astrocytes express the highest rate of connexins (Cxs), the protein constituents of gap junction channels that provide the molecular basis for direct cellto-cell communication. Though astrocytes were initially thought to form a glial syncitium, there is now evidence for a more specialized network organization (5). As increasing evidence argues for dynamic interactions between neurons and astrocytes (6), a coordinated population of astrocytes working in concert with neurons could contribute to sensory integration occurring in OG. The goal of this study is to determine how Cx-mediated intercellular communication in astrocytes is organized and modulated in this brain structure characterized by functional units. Features of OG astrocytes studied so far include their morphology (7,8), membrane...

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“…To further characterize the cellular elements comprising a glomerulus we used GFAP-IR to visualize the glial processes (cf. Bailey and Shipley, 1993;Chiu and Greer, 1996). GFAP-IR processes were observed throughout the olfactory nerve layer, glomerular layer, and external plexiform layer.…”

Section: Characterization Of Axonal and Dendritic Processes By Omp Mmentioning

confidence: 98%