The roles of T-type calcium channel in the development of neuropathic pain following chronic compression of rat dorsal root ganglia.

This study aimed to elucidate the role of T-type calcium channels in the nociceptive signal transmission at the spinal level. The chronic compression of dorsal root ganglion (CCD) rat model was adopted. Three doses (50, 100 and 200 microg in groups Mib50, Mib100 and Mib200, respectively) of specific T-type Ca2+ channel inhibitors mibefradil (Mib) or normal saline (NS) were intrathecally administered on the 5th day after the CCD model had been established. The paw withdrawal latency from a noxious thermal stimulus and paw withdrawal mechanical threshold of von Frey filament was used to measure the thermal hyperalgesia and tactile allodynia, respectively. Lumbar spinal cords of the rats isolated on the 5th day after the operation were prepared to measure the mRNA expression of T-type (Cav3.1, Cav3.2 and Cav3.3) calcium channel with RT-PCR methods. The results demonstrated that CCD rats produced reliable thermal hyperalgesia and tactile allodynia after surgery. The intrathecal administration of Mib significantly suppressed thermal hyperalgesia and allodynia in CCD rats (p< 0.01), and the inhibitory effect lasted for 2 h. However, only Cav3.2 and Cav3.3 T-type calcium channel mRNA were detected in the lumbar spinal cord of rats, and there were no Cav3.1 calcium channels. Compared with native and sham groups, the Cav3.2 and Cav3.3 calcium channel mRNA expression increased significantly (p < 0.05). These data support the view that spinal T-type calcium (Cav3.2 and Cav3.3 but not Cav3.1) channels may play an important role in the pathogenesis of neuropathic pain.

Wen XJ ，Xu SY ，Chen ZX ，Yang CX ，Liang H ，Li H ... -  《-》

Intrathecal administration of Cav3.2 and Cav3.3 antisense oligonucleotide reverses tactile allodynia and thermal hyperalgesia in rats following chronic compression of dorsal root of ganglion.

Wen XJ ，Li ZJ ，Chen ZX ，Fang ZY ，Yang CX ，Li H ，Zeng YM ... -  《ACTA PHARMACOLOGICA SINICA》

Hyperalgesia induced by spinal and peripheral hydrogen sulfide: evidence for involvement of Cav3.2 T-type calcium channels.

Maeda Y ，Aoki Y ，Sekiguchi F ，Matsunami M ，Takahashi T ，Nishikawa H ，Kawabata A ... -  《-》

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

Yue J ，Liu L ，Liu Z ，Shu B ，Zhang Y ... -  《-》

Effects of intrathecal injection of prednisolone acetate on expression of NR2B subunit and nNOS in spinal cord of rats after chronic compression of dorsal root ganglia.

Ma ZL ，Zhang W ，Gu XP ，Yang WS ，Zeng YM ... -  《ANNALS OF CLINICAL AND LABORATORY SCIENCE》