Referenced in: none

Automatically associated channels: Cav3.2 , Cav3.3

Title: Upregulation of T-type Ca2+ channels in primary sensory neurons in spinal nerve injury.

Authors: Jing Yue, Lieju Liu, Zhiguo Liu, Bin Shu, Yi Zhang

Journal, date & volume: Spine, 2013 Mar 15 , 38, 463-70

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22972512

Abstract
Painful behavior testing, whole-cell patch clamp recordings, and PCR analysis were served to test the influence of T-type Ca channels in spinal nerve-injured rats.To determine the changes of T-type Ca channels in dorsal root ganglion (DRG) neurons of different sizes and the contribution to neuronal firing and painful behavior in neuropathic pain induced by nerve injury.T-type and high-voltage-activated Ca channels play an important role in the transmission of nociceptive signals, especially in neuronal hyperexcitability in neuropathic pain. However, little is known about how nerve injury affects T-type Ca channels in DRG neurons of different sizes.The effect of intrathecal administration of mibefradil in nerve-ligated rats was examined by painful behavior testing and current clamp. The changes of T-type Ca channels in DRG neurons caused by spinal nerve ligation were determined by RT-PCR analysis and voltage clamp.Spinal nerve injury significantly increased current density of T-type Ca channels in small DRG neurons. In addition, nerve injury significantly increased the percentage of T-type Ca channels in medium and large DRG neurons. Nerve injury significantly increased the mRNA levels of Cav3.2 and Cav3.3 in DRGs. Block of T-type Ca channels on mibefradil administration significantly normalized painful behavior and hyperexcitability in neuronal firing in spinal nerve-injured rats.Our study first indicated the upregulation of functional T-type Ca channels in DRG neurons of different sizes and the changes in different subtypes of T-type Ca channels by spinal nerve injury. Considering the effect of blocking T-type Ca channels in painful behavior and abnormal neuronal firing in rats with nerve injury, our results suggest that T-type Ca channels are potential therapeutic targets for the treatment of spinal nerve ligation-induced neuropathic pain.