title: Expression of A-type K channel alpha subunits Kv 4.2 and Kv 4.3 in rat spinal lamina II excitatory interneurons and colocalization with pain-modulating molecules.
abstract: Voltage-gated K(+) channel alpha subunits Kv 4.2 and Kv 4.3 are the major contributors of somatodendritic A-type K(+) currents in many CNS neurons. A recent hypothesis suggests that Kv 4 subunits may be involved in pain modulation in dorsal horn neurons. However, whether Kv 4 subunits are expressed in dorsal horn neurons remains unknown. Using immunohistochemistry, we found that Kv 4.2 and Kv 4.3 immunoreactivity was concentrated in the superficial dorsal horn, mainly in lamina II. Both Kv 4.2 and Kv 4.3 appeared on many rostrocaudally orientated dendrites, whereas Kv 4.3 could be also detected from certain neuronal somata. Kv 4.3(+) neurons were a subset of excitatory inerneurons with calretinin(+)/calbindin(-)/PKCgamma(-) markers, and a fraction of them expressed micro-opioid receptors. Kv 4.3(+) neurons also expressed ERK 2 and mGluR 5, which are molecules related to the induction of central sensitization, a mechanism mediating nociceptive plasticity. Together with the expression of Kv 4.3 in VR 1(+) DRG neurons, our data suggest that Kv C4 subunits could be involved in pain modulation.
authors.affiliation: Institute of Neuroscience, National Yang-Ming University, Brain Research Centre, University System of Taiwan, Taipei, Taiwan 112, Republic of China.
authors.forename: Hsin-Yi
authors.initials: HY
authors.lastname: Huang
authors.forename: Jen-Kun
authors.initials: JK
authors.lastname: Cheng
authors.forename: Yang-Hsin
authors.initials: YH
authors.lastname: Shih
authors.forename: Pei-Hsuan
authors.initials: PH
authors.lastname: Chen
authors.forename: Chin-Lin
authors.initials: CL
authors.lastname: Wang
authors.forename: Meei-Ling
authors.initials: ML
authors.lastname: Tsaur
mesh_terms: D000818:Animals; D015153:Blotting, Western / Q000379:methods; D064032:Calbindin 2; D005727:Ganglia, Spinal / Q000166:cytology; D005786:Gene Expression Regulation / Q000502:physiology*; D007150:Immunohistochemistry / Q000379:methods; D007395:Interneurons / Q000378:metabolism*; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D010146:Pain / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D051672:Shal Potassium Channels / Q000235:genetics / Q000378:metabolism*; D013116:Spinal Cord / Q000166:cytology*; D016708:Synaptophysin / Q000378:metabolism
chemical_list: C576512:Calb2 protein, rat; D064032:Calbindin 2; C489787:MAP2 protein, rat; D008869:Microtubule-Associated Proteins; D010320:Parvalbumins; D021122:Protein Subunits; D064030:S100 Calcium Binding Protein G; D051672:Shal Potassium Channels; D016708:Synaptophysin; C087857:protein kinase C gamma; D011493:Protein Kinase C