Brain research bulletin
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Brain research bulletin · Jan 2012
Activation of astrocytes in the anterior cingulate cortex contributes to the affective component of pain in an inflammatory pain model.
The anterior cingulate cortex (ACC) has been implicated as a key structure in the affective component of pain (such as unpleasantness or aversion). Recent evidence suggests that activation of spinal astrocytes contributes to the development and maintenance of the sensory component of pain after peripheral inflammation. However, whether the astrocytes in the ACC contribute to the affective component of pain is unknown. ⋯ Similarly, Western blot also revealed enhanced expression of GFAP protein at 3 d and 14 d after CFA injection. Interestingly, intra-ACC injection of L-alpha-aminoadipate (L-α-AA), an astroglial toxin, inhibited the escape/avoidance behavior, but did not affect the paw withdrawal threshold at 3d following CFA injection. All together, our results suggest that the astrocytes activation in the ACC may contribute to the affective component of pain.
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Brain research bulletin · Jan 2012
Acute neuregulin-1 signaling influences AMPA receptor mediated responses in cultured cerebellar granule neurons.
Neuregulin-1 (NRG1) is a trophic and differentiation factor that signals through ErbB receptor tyrosine kinases to regulate nervous system development. Previous studies have demonstrated that NRG1 affects plasticity at glutamatergic synapses in principal glutamatergic neurons of the hippocampus and frontal cortex; however, immunohistochemical and genetic analyses strongly suggest these effects are indirect and mediated via ErbB4 receptors on GABAergic interneurons. Here, we used cultured cerebellar granule cells (CGCs) that express ErbB4 to analyze the cell-autonomous effects of NRG1 stimulation on glutamatergic function. ⋯ CGCs in our cultures conditions express low levels of GluR1, in contrast to dissociated hippocampal cultures, but do express the long isoform of GluR4. This study provides first evidence that (1) high-glycine can induce plasticity at glutamatergic synapses in CGCs, and (2) that acute NRG1/ErbB-signaling can regulate glutamatergic plasticity in CGCs. Taken together with previous reports, our results suggest that, similar to Schaeffer collateral to CA1 synapses, NRG1 effects are activity dependent and mediated via modulation of synaptic AMPARs.
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Brain research bulletin · Jan 2012
Role of puerarin in the signalling of neuropathic pain mediated by P2X3 receptor of dorsal root ganglion neurons.
Tissue injury or inflammation of the nervous system may result in chronic neuropathic pain characterized by sensitivity to painful stimuli. P2X(3) receptors play a crucial role in facilitating pain transmission. Puerarin is an active compound of a traditional Chinese medicine Ge-gen, and Ge-gen soup has anti-inflammatory effects. ⋯ At day 7-10 after operation, MWT and TWL in group CCI+PUE was higher than those in group CCI, but there was no significant difference between group CCI+PUE and group Ctrl (p>0.05). At day 14 after operation, the stain values of P2X(3) proteins and mRNAs in L4/L5 DRG of group CCI were higher than those in group Ctrl, Sham, Ctrl+PUE and CCI+PUE, while the stain values of P2X(3) proteins and mRNAs in group CCI+PUE were significantly decreased compared with those in group CCI. Therefore, puerarin may alleviate neuropathic pain mediated by P2X(3) receptors in dorsal root ganglion neurons.