Involvement of Voltage-Gated Sodium Channel NaV1.8 in the Regulation of the Release and Synthesis of Substance P in Adult Mouse Dorsal Root Ganglion Neurons

• Main Authors: He-Bin Tang (Author), Eri Shiba (Author), Yu-Sang Li (Author), Norimitsu Morioka (Author), Tai-Xing Zheng (Author), Nobukuni Ogata (Author), Yoshihiro Nakata (Author)
• Format: Book
• Published: Elsevier, 2008-01-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

This study was conducted to determine whether Nav1.8 contributes to the release and/or synthesis of substance P (SP) in adult mice dorsal root ganglion (DRG) neurons. The SP released from cultured DRG neurons of Nav1.8 knock-out mice exposed to either capsaicin or KCl was significantly lower than that from wild-type (C57BL/6) mice based on a radioimmunoassay. The SP level of L6 DRG in Nav1.8 knock-out mice was also lower than that in wild-type mice. After chronic constriction injury (CCI) of the sciatic nerve, the level of SP decreased in the L6 ipsilateral DRG of wild-type but not Nav1.8 knock-out mice. The preprotachykinin-A (PPT-A) mRNAs in L4 -6 DRGs of Nav1.8 knock-out mice also fell to half their normally abundant levels of expression. There were significant increases in Nav1.8 expression of the L6 contralateral DRG from wild-type mice and in the percentage of neurons expressing neurokinin-1 receptor in the cytosol of L6 DRGs from wild-type or Nav1.8 knock-out mice. These findings suggest that Nav1.8 is involved in the regulation of the release and synthesis of SP in the DRG neurons of wild-type mice. Keywords:: dorsal root ganglion (DRG), chronic constriction injury (CCI), Nav1.8 knock-out mice, preprotachykinin-A (PPT-A) mRNA, substance P (SP)

Item Description

1347-8613
10.1254/jphs.08163FP