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.
N-methyl-D-aspartate receptor subunit 2B (NR2B) and neuronal nitric oxide synthase (nNOS) play important roles in the mechanism of neuropathic pain. To elucidate how glucocorticoids affect this mechanism, we studied the effects of intrathecal (it) injection of prednisolone acetate (PA) on a nociceptive stimulus and the changes of nNOS and NR2B subunit expression in the spinal dorsal horn of Sprague Dawley rats following chronic compression of the dorsal root ganglia (CCD). Paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) were measured for 15 days postoperatively. An it injection of PA (2.0 mg/kg) every 3 days for postoperative days 1 to 15 inhibited the thermal hyperalgesia and tactile allodynia of CCD rats. Chronic compression of the dorsal root ganglia induced time-dependent upregulation of nNOS and NR2B subunits of N-methyl-D-aspartate receptor within the spinal cord dorsal horn ipsilateral to CCD. Both upregulations were significantly diminished by it administration of PA (2.0 mg/kg), but not by lower doses of PA (0.5 or 1.0 mg/kg). The results suggest that PA upregulation of neuronal nitric oxide synthase and NR2B subunit expression in the spinal dorsal horn contributes to PA inhibition of hyperalgesia induced by chronic compression of dorsal root ganglia.
Ma
Zheng-Liang
ZL
Department of Anesthesiology, Drum Tower Hospital, Nanjing University, Nanjing 210008, Jiangsu Province, China. mazhengliang1964@yahoo.com.cn
Zhang
Wei
W
Gu
Xiao-Ping
XP
Yang
Wen-Sheng
WS
Zeng
Yin-Ming
YM
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000627:therapeutic use; D002908:Chronic Disease; D004195:Disease Models, Animal; D005727:Ganglia, Spinal / Q000503:physiopathology*; D007150:Immunohistochemistry; D007278:Injections, Spinal; D009408:Nerve Compression Syndromes / Q000188:drug therapy* / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism*; D010147:Pain Measurement; D011239:Prednisolone / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism*
D000893:Anti-Inflammatory Agents; C121001:NR2B NMDA receptor; D016194:Receptors, N-Methyl-D-Aspartate; C009935:prednisolone acetate; D011239:Prednisolone; D052248:Nitric Oxide Synthase Type I