Research Report Postnatal change of GluR5 kainate receptor expression in the substantia gelatinosa neuron of the trigeminal subnucleus caudalis in mice Seon Ah Park a , Hua Yin a , Janardhan P. Bhattarai a , Soo Joung Park a , Jeong Chae Lee c , Chul Jin Kim d , Seong Kyu Han a,b, ⁎ a Department of Oral Physiology and BK21 program, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, 561-756, Republic of Korea b Laboratory for Oral diseases-related Compounds, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, 561-756, Republic of Korea c Laboratory of Cell Biology in Department of Orthodontics, School of Dentistry and Institute of Oral Bioscience, Chonbuk National University, Jeonju, 561-756, Republic of Korea d Cerebrovascular Laboratory-Department of Neurosurgery, Research Institute of Clinical Medicine, Chonbuk National University Medical School & Hospital, Chonbuk National University, Jeonju, 561-756, Republic of Korea ARTICLE INFO ABSTRACT Article history: Accepted 23 May 2010 Available online 1 June 2010 The substantia gelatinosa (SG) of the trigeminal subnucleus caudalis (Vc) has been implicated in the processing of nociceptive information from the orofacial region. Kainate receptors (KARs) play an important role in sensory transmission. Five different KAR subunits have been cloned and the expression of the KAR subunits showed developmental changes. In this study, RT-PCR, western blotting, immunohistochemistry and a patch clamp technique were used examine the functional expression of the GluR5 subunit in the SG of the Vc in juvenile, peripubertal and/or adult mice. The levels of mRNA and protein expression of the GluR5 subunit in the SG of the Vc were higher in the juvenile mice than in the peripubertal or adult mice. In addition, the KA and ATPA, a GluR5 KAR agonist, induced membrane depolarization on the SG neurons in both juvenile and adult mice in a concentration-dependent manner. However, the juvenile SG neurons showed a stronger response to KA and ATPA than those of adults. The membrane depolarization by KA was suppressed slightly in the presence of the AMPA receptor antagonist, GYKI 52466. These results show that the GluR5 KAR subunits are expressed functionally on the SG neurons of the Vc in mice, and the expression levels of the GluR5 subunits decrease with postnatal development. These postnatal changes in the GluR5 KAR subunit may be a possible mechanism for age-dependent pain processing. © 2010 Elsevier B.V. All rights reserved. Keywords: Kainate Trigeminal subnucleus caudalis Substantia gelatinosa Patch clamp RT-PCR Western blot GluR5 BRAIN RESEARCH 1346 (2010) 52 – 61 ⁎ Corresponding author. Department of Oral Physiology & Institute of Oral Bioscience, School of Dentistry, Chonbuk National University, Jeonju, 561-756, Republic of Korea. Fax: +82 63 270 4028. E-mail address: skhan@chonbuk.ac.kr (S.K. Han). 0006-8993/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.brainres.2010.05.065 available at www.sciencedirect.com www.elsevier.com/locate/brainres