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 µg 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