Expression and localization of Kv1 potassium channels in rat dorsal and ventral spinal roots.
We investigated the expression and localization of Kv1 channels in dorsal spinal roots (DRs) and ventral spinal roots (VRs) in rats. Among Kv1.1-1.6 tested by RT-PCR, mRNAs of Kv1.1, 1.2, and 1.5 were moderately expressed, those of Kv1.3 and Kv1.6 were weakly expressed, and that of Kv1.4 was hardly expressed at all in both DRs and VRs, whereas all six mRNAs were detected in spinal cord. Western blotting revealed that the major immunoreactive proteins were Kv1.1 and Kv1.2 in both DRs and VRs. Quantitative analysis indicated that levels of Kv1.1 and Kv1.2 protein were significantly higher in DRs than VRs. Immunohistochemical examination showed that Kv1.1 and Kv1.2 were colocalized in juxtaparanodal regions of axons in both DRs and VRs. Finally, immunoprecipitation experiments revealed that Kv1.1 and Kv1.2 were coassembled. These findings indicate that Kv1 subtypes in DRs and VRs are somewhat different from those in spinal cord, and that the numbers of Kv1.1 and Kv1.2 channels are higher in DRs than VRs.
Department of Pharmacotherapeutics, Showa Pharmaceutical University, Machida, Tokyo, Japan. utsunomi@ac.shoyaku.ac.jp
Iku
I
Utsunomiya
Eikichi
E
Yoshihashi
Shinya
S
Tanabe
Yoshihiko
Y
Nakatani
Hideaki
H
Ikejima
Tadashi
T
Miyatake
Keiko
K
Hoshi
Kyoji
K
Taguchi
D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism; D045744:Cell Line, Tumor; D015870:Gene Expression / Q000502:physiology*; D006603:Hexuronic Acids / Q000276:immunology / Q000378:metabolism; D047468:Immunoprecipitation / Q000379:methods; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D009413:Nerve Fibers, Myelinated / Q000378:metabolism; D009447:Neuroblastoma; D018408:Patch-Clamp Techniques; D019887:Peanut Agglutinin / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000378:metabolism; D051637:Shaker Superfamily of Potassium Channels / Q000235:genetics / Q000378:metabolism*; D013126:Spinal Nerve Roots / Q000033:anatomy & histology* / Q000378:metabolism*; D014162:Transfection / Q000379:methods
D015816:Cell Adhesion Molecules, Neuronal; C105177:Cntnap1 protein, rat; D006603:Hexuronic Acids; D019887:Peanut Agglutinin; D012333:RNA, Messenger; D051637:Shaker Superfamily of Potassium Channels; C065803:N-acetylgalactosaminuronic acid; D011188:Potassium