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The principal neurons of the medial nucleus of the trapezoid body and NG2(+) glial cells receive coordinated excitatory synaptic input.

Müller J, Reyes-Haro D, Pivneva T, Nolte C, Schaette R, Lübke J, Kettenmann H - J. Gen. Physiol. (2009)

Bottom Line: In contrast to the principal neurons, which are known to receive excitatory as well as inhibitory inputs, the NG2 glia receive mostly, if not exclusively, alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid receptor-mediated evoked and spontaneous synaptic input.Simultaneous recordings from neurons and NG2 glia indicate that they partially receive synchronized spontaneous input.This shows that an NG2(+) glial cell and a postsynaptic neuron share presynaptic terminals.

View Article: PubMed Central - PubMed

Affiliation: Zelluläre Neurowissenschaften, Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany.

ABSTRACT
Glial cell processes are part of the synaptic structure and sense spillover of transmitter, while some glial cells can even receive direct synaptic input. Here, we report that a defined type of glial cell in the medial nucleus of the trapezoid body (MNTB) receives excitatory glutamatergic synaptic input from the calyx of Held (CoH). This giant glutamatergic terminal forms an axosomatic synapse with a single principal neuron located in the MNTB. The NG2 glia, as postsynaptic principal neurons, establish synapse-like structures with the CoH terminal. In contrast to the principal neurons, which are known to receive excitatory as well as inhibitory inputs, the NG2 glia receive mostly, if not exclusively, alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid receptor-mediated evoked and spontaneous synaptic input. Simultaneous recordings from neurons and NG2 glia indicate that they partially receive synchronized spontaneous input. This shows that an NG2(+) glial cell and a postsynaptic neuron share presynaptic terminals.

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Identification of glial cells in the MNTB. (A) Astrocytes and NG2 glia in the MNTB of a GFAP-eGFP transgenic mouse. Images are overlays of five consecutive confocal sections taken 1-μm apart. The images are the overlays of eGFP (green) and Alexa 594 emission (magenta). Note that white color in the NG2 glia (right image) is not colocalization but is due to the z-stack projection. Asterisks indicate neighboring postsynaptic principal neurons. White arrow in the left image indicates weakly eGFP+ glia. The scale bar (20 μm) refers to all pictures. (B) Electrophysiological identification of astrocyte and NG2 glia. (Top) Representative current responses from an astrocyte (left) and an NG2 glia (right) evoked by step voltages. Membrane currents were evoked by 50-ms voltage steps ranging from −160 to 40 mV from a holding potential of −70 mV. Scale bars refer to both graphs. (Bottom) Average current–voltage (IV) plots (n = 25). Data are mean ± SD. (C) MNTB glial cells with a complex current pattern and sPSCs are expressing AN2 antigen. Image on the left is an overlay of the two images on the right, showing a single focal plane of an NG2 glia filled with LY through the patch pipette (green), fixed after recording and proceeded for immunostaining with AN2 antibody (magenta; see Materials and methods). The asterisks indicate a neighboring principal neuron. The scale bar (20 μm) refers to all pictures.
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fig1: Identification of glial cells in the MNTB. (A) Astrocytes and NG2 glia in the MNTB of a GFAP-eGFP transgenic mouse. Images are overlays of five consecutive confocal sections taken 1-μm apart. The images are the overlays of eGFP (green) and Alexa 594 emission (magenta). Note that white color in the NG2 glia (right image) is not colocalization but is due to the z-stack projection. Asterisks indicate neighboring postsynaptic principal neurons. White arrow in the left image indicates weakly eGFP+ glia. The scale bar (20 μm) refers to all pictures. (B) Electrophysiological identification of astrocyte and NG2 glia. (Top) Representative current responses from an astrocyte (left) and an NG2 glia (right) evoked by step voltages. Membrane currents were evoked by 50-ms voltage steps ranging from −160 to 40 mV from a holding potential of −70 mV. Scale bars refer to both graphs. (Bottom) Average current–voltage (IV) plots (n = 25). Data are mean ± SD. (C) MNTB glial cells with a complex current pattern and sPSCs are expressing AN2 antigen. Image on the left is an overlay of the two images on the right, showing a single focal plane of an NG2 glia filled with LY through the patch pipette (green), fixed after recording and proceeded for immunostaining with AN2 antibody (magenta; see Materials and methods). The asterisks indicate a neighboring principal neuron. The scale bar (20 μm) refers to all pictures.

Mentions: We identified two types of glial cells in close association with the CoH synapse that could be distinguished from each other by their eGFP fluorescence in GFAP-eGFP transgenic mice (Nolte et al., 2001). One type was highly fluorescent, with numerous ramified processes (Fig. 1 A, left). The second type was not or only weakly fluorescent (Fig. 1 A, left, arrow).


The principal neurons of the medial nucleus of the trapezoid body and NG2(+) glial cells receive coordinated excitatory synaptic input.

Müller J, Reyes-Haro D, Pivneva T, Nolte C, Schaette R, Lübke J, Kettenmann H - J. Gen. Physiol. (2009)

Identification of glial cells in the MNTB. (A) Astrocytes and NG2 glia in the MNTB of a GFAP-eGFP transgenic mouse. Images are overlays of five consecutive confocal sections taken 1-μm apart. The images are the overlays of eGFP (green) and Alexa 594 emission (magenta). Note that white color in the NG2 glia (right image) is not colocalization but is due to the z-stack projection. Asterisks indicate neighboring postsynaptic principal neurons. White arrow in the left image indicates weakly eGFP+ glia. The scale bar (20 μm) refers to all pictures. (B) Electrophysiological identification of astrocyte and NG2 glia. (Top) Representative current responses from an astrocyte (left) and an NG2 glia (right) evoked by step voltages. Membrane currents were evoked by 50-ms voltage steps ranging from −160 to 40 mV from a holding potential of −70 mV. Scale bars refer to both graphs. (Bottom) Average current–voltage (IV) plots (n = 25). Data are mean ± SD. (C) MNTB glial cells with a complex current pattern and sPSCs are expressing AN2 antigen. Image on the left is an overlay of the two images on the right, showing a single focal plane of an NG2 glia filled with LY through the patch pipette (green), fixed after recording and proceeded for immunostaining with AN2 antibody (magenta; see Materials and methods). The asterisks indicate a neighboring principal neuron. The scale bar (20 μm) refers to all pictures.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC2717692&req=5

fig1: Identification of glial cells in the MNTB. (A) Astrocytes and NG2 glia in the MNTB of a GFAP-eGFP transgenic mouse. Images are overlays of five consecutive confocal sections taken 1-μm apart. The images are the overlays of eGFP (green) and Alexa 594 emission (magenta). Note that white color in the NG2 glia (right image) is not colocalization but is due to the z-stack projection. Asterisks indicate neighboring postsynaptic principal neurons. White arrow in the left image indicates weakly eGFP+ glia. The scale bar (20 μm) refers to all pictures. (B) Electrophysiological identification of astrocyte and NG2 glia. (Top) Representative current responses from an astrocyte (left) and an NG2 glia (right) evoked by step voltages. Membrane currents were evoked by 50-ms voltage steps ranging from −160 to 40 mV from a holding potential of −70 mV. Scale bars refer to both graphs. (Bottom) Average current–voltage (IV) plots (n = 25). Data are mean ± SD. (C) MNTB glial cells with a complex current pattern and sPSCs are expressing AN2 antigen. Image on the left is an overlay of the two images on the right, showing a single focal plane of an NG2 glia filled with LY through the patch pipette (green), fixed after recording and proceeded for immunostaining with AN2 antibody (magenta; see Materials and methods). The asterisks indicate a neighboring principal neuron. The scale bar (20 μm) refers to all pictures.
Mentions: We identified two types of glial cells in close association with the CoH synapse that could be distinguished from each other by their eGFP fluorescence in GFAP-eGFP transgenic mice (Nolte et al., 2001). One type was highly fluorescent, with numerous ramified processes (Fig. 1 A, left). The second type was not or only weakly fluorescent (Fig. 1 A, left, arrow).

Bottom Line: In contrast to the principal neurons, which are known to receive excitatory as well as inhibitory inputs, the NG2 glia receive mostly, if not exclusively, alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid receptor-mediated evoked and spontaneous synaptic input.Simultaneous recordings from neurons and NG2 glia indicate that they partially receive synchronized spontaneous input.This shows that an NG2(+) glial cell and a postsynaptic neuron share presynaptic terminals.

View Article: PubMed Central - PubMed

Affiliation: Zelluläre Neurowissenschaften, Max-Delbrück-Centrum für Molekulare Medizin, Berlin, Germany.

ABSTRACT
Glial cell processes are part of the synaptic structure and sense spillover of transmitter, while some glial cells can even receive direct synaptic input. Here, we report that a defined type of glial cell in the medial nucleus of the trapezoid body (MNTB) receives excitatory glutamatergic synaptic input from the calyx of Held (CoH). This giant glutamatergic terminal forms an axosomatic synapse with a single principal neuron located in the MNTB. The NG2 glia, as postsynaptic principal neurons, establish synapse-like structures with the CoH terminal. In contrast to the principal neurons, which are known to receive excitatory as well as inhibitory inputs, the NG2 glia receive mostly, if not exclusively, alpha-amino-3-hydroxy-5-methyl-isoxazole-4-propionic acid receptor-mediated evoked and spontaneous synaptic input. Simultaneous recordings from neurons and NG2 glia indicate that they partially receive synchronized spontaneous input. This shows that an NG2(+) glial cell and a postsynaptic neuron share presynaptic terminals.

Show MeSH
Related in: MedlinePlus