Sensory and cortical activation of distinct glial cell subtypes in the somatosensory thalamus of young rats.

The European journal of neuroscience (2010-07-09)
H Rheinallt Parri, Timothy M Gould, Vincenzo Crunelli
RESUMEN

The rodent ventrobasal (VB) thalamus receives sensory inputs from the whiskers and projects to the cortex, from which it receives reciprocal excitatory afferents. Much is known about the properties and functional roles of these glutamatergic inputs to thalamocortical neurons in the VB, but no data are available on how these afferents can affect thalamic glial cells. In this study, we used combined electrophysiological recordings and intracellular calcium ([Ca(2+)](i)) imaging to investigate glial cell responses to synaptic afferent stimulation. VB thalamus glial cells can be divided into two groups based on their [Ca(2+)](i) and electrophysiological responses to sensory and corticothalamic stimulation. One group consists of astrocytes, which stain positively for S100B and preferentially load with SR101, have linear current-voltage relations and low input resistance, show no voltage-dependent [Ca(2+)](i) responses, but express mGluR5-dependent [Ca(2+)](i) transients following stimulation of the sensory and/or corticothalamic excitatory afferent pathways. Cells of the other glial group, by contrast, stain positively for NG2, and are characterized by high input resistance, the presence of voltage-dependent [Ca(2+)](i) elevations and voltage-gated inward currents. There were no synaptically induced [Ca(2+)](i) elevations in these cells under control conditions. These results show that thalamic glial cell responses to synaptic input exhibit different properties to those of thalamocortical neurons. As VB astrocytes can respond to synaptic stimulation and signal to neighbouring neurons, this glial cell organization may have functional implications for the processing of somatosensory information and modulation of behavioural state-dependent thalamocortical network activities.

MATERIALES
Referencia del producto
Marca
Descripción del producto

Sigma-Aldrich
Anti-NG2 Chondroitin Sulfate Proteoglycan Antibody, Chemicon®, from rabbit
Sigma-Aldrich
Monoclonal Anti-S-100 (β-Subunit) antibody produced in mouse, clone SH-B1, ascites fluid
Sigma-Aldrich
Anti-S-100 antibody produced in rabbit, IgG fraction of antiserum, buffered aqueous solution
Sigma-Aldrich
Dihydrokainic acid, ≥98% (HPLC), powder
Sigma-Aldrich
Anti-NG2 Antibody, clone 132.38, clone 132.38, Upstate®, from mouse