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Mol. Cells 2010; 30(5): 461-466

Published online November 30, 2010

https://doi.org/10.1007/s10059-010-0140-x

© The Korean Society for Molecular and Cellular Biology

NMDA Receptor, PKC and ERK Mediate Fos Expression Induced by the Activation of Group I Metabotropic Glutamate Receptors in the Spinal Trigeminal Subnucleus Oralis

Eun-sung Park, So-yeon Kim, and Dong-Ho Youn*

Department of Oral Physiology, School of Dentistry and Brain Korea 21, Brain Science and Engineering Institute, Kyungpook National University, Daegu 700-412, Korea

Correspondence to : *Correspondence: dyoun@knu.ac.kr

Received: June 8, 2010; Revised: August 16, 2010; Accepted: August 23, 2010

Abstract

Fos, a protein product of immediate early gene c-fos, has been used as a marker for activation of nociceptive neu-rons in central nervous system including spinal trigeminal nucleus (Vsp). By noxious stimulation applied to orofacial area, the expression of Fos occurred in the Vsp pars oralis (Vo), the subnucleus receiving inputs from trigeminal primary afferents that predominantly innervate intraoral receptive fields. The present study demonstrates that the in vitro activation of group I metabotropic glutamate receptors (mGluRs; mGluR1 and 5) by bath-application of their well-known agonist (S)-3,5-dihydroxyphenylglycine (DHPG) increased the number of Fos-expressing neurons in the Vo area. In addition, bath application of DHPG caused inward currents, a parameter of neuronal excitation, in the Vo neurons held at -70 mV in voltage-clamp mode of whole-cell recordings. In further experiments characterizing two phenomena, the increased Fos expression in the Vo was mediated by an additive activation of both mGluR1 and mGluR5, which required the activation of N-methyl-D-aspartate (NMDA) receptors, protein kinase C (PKC) and extracellular signal-regulated kinase (ERK). In contrast, the inward currents were mediated only by mGluR1, but not by others. The data resulting from this in vitro study indicate that the DHPG-induced membrane depolarisation or neuronal excitation may be upstream to, or skip, the NMDA receptor, PKC and ERK pathways for the DHPG-induced Fos expression.

Keywords ERK, group I metabotropic glutamate receptor, NMDA receptor, PKC, spinal trigeminal nucleus

Article

Research Article

Mol. Cells 2010; 30(5): 461-466

Published online November 30, 2010 https://doi.org/10.1007/s10059-010-0140-x

Copyright © The Korean Society for Molecular and Cellular Biology.

NMDA Receptor, PKC and ERK Mediate Fos Expression Induced by the Activation of Group I Metabotropic Glutamate Receptors in the Spinal Trigeminal Subnucleus Oralis

Eun-sung Park, So-yeon Kim, and Dong-Ho Youn*

Department of Oral Physiology, School of Dentistry and Brain Korea 21, Brain Science and Engineering Institute, Kyungpook National University, Daegu 700-412, Korea

Correspondence to:*Correspondence: dyoun@knu.ac.kr

Received: June 8, 2010; Revised: August 16, 2010; Accepted: August 23, 2010

Abstract

Fos, a protein product of immediate early gene c-fos, has been used as a marker for activation of nociceptive neu-rons in central nervous system including spinal trigeminal nucleus (Vsp). By noxious stimulation applied to orofacial area, the expression of Fos occurred in the Vsp pars oralis (Vo), the subnucleus receiving inputs from trigeminal primary afferents that predominantly innervate intraoral receptive fields. The present study demonstrates that the in vitro activation of group I metabotropic glutamate receptors (mGluRs; mGluR1 and 5) by bath-application of their well-known agonist (S)-3,5-dihydroxyphenylglycine (DHPG) increased the number of Fos-expressing neurons in the Vo area. In addition, bath application of DHPG caused inward currents, a parameter of neuronal excitation, in the Vo neurons held at -70 mV in voltage-clamp mode of whole-cell recordings. In further experiments characterizing two phenomena, the increased Fos expression in the Vo was mediated by an additive activation of both mGluR1 and mGluR5, which required the activation of N-methyl-D-aspartate (NMDA) receptors, protein kinase C (PKC) and extracellular signal-regulated kinase (ERK). In contrast, the inward currents were mediated only by mGluR1, but not by others. The data resulting from this in vitro study indicate that the DHPG-induced membrane depolarisation or neuronal excitation may be upstream to, or skip, the NMDA receptor, PKC and ERK pathways for the DHPG-induced Fos expression.

Keywords: ERK, group I metabotropic glutamate receptor, NMDA receptor, PKC, spinal trigeminal nucleus

Mol. Cells
Sep 30, 2022 Vol.45 No.9, pp. 603~672
COVER PICTURE
The Target of Rapamycin Complex (TORC) is a central regulatory hub in eukaryotes, which is well conserved in diverse plant species, including tomato (Solanum lycopersicum). Inhibition of TORC genes (SlTOR, SlLST8, and SlRAPTOR) by VIGS (virus-induced gene silencing) results in early fruit ripening in tomato. The red/ orange tomatoes are early-ripened TORC-silenced fruits, while the green tomato is a control fruit. Top, left, control fruit (TRV2-myc); top, right, TRV2-SlLST8; bottom, left, TRV2-SlTOR; bottom, right, TRV2-SlRAPTOR(Choi et al., pp. 660-672).

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