The effect of intrathecal gabapentin on mechanical and thermal hyperalgesia in neuropathic rats induced by spinal nerve ligation.
Gabapentin decreases the level of glutamate and elevates that of alpha-amino-butyric acid in the central nervous system. Gabapentin was shown to have antinociceptive effects in several facilitated pain models. Intrathecal gabapentin was also known to be effective in reducing mechanical allodynia in animals with neuropathic pain. In this study, we investigated to see whether intrathecal gabapentin produces antihyperalgesic effects on thermal and mechanical hyperalgesia in neuropathic rats and whether its effects are associated with motor impairment. To induce neuropathic pain in Sprague-Dawley rats, left L5 and L6 spinal nerves were ligated. After a week, lumbar catheterization into subarachnoid space was performed. Then, paw withdrawal times to thermal stimuli and vocalization thresholds to paw pressure were determined before and up to 2 hr after intrathecal injection of gabapentin. Also, motor functions including performance times on rota-rod were determined. Intrathecal gabapentin attenuated significantly thermal and mechanical hyperalgesia in neuropathic rats, but did not block thermal and mechanical nociception in sham-operated rats. Intrathecal gabapentin of antihyperalgesic doses inhibited motor coordination performance without evident ambulatory dysfunction. This study demonstrates that intrathecal gabapentin is effective against thermal and mechanical hyperalgesia, in spite of moderate impairment of motor coordination.
Cho
Hyun Sung
HS
Department of Anesthesiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
Kim
Myung Hee
MH
Choi
Duck Hwan
DH
Lee
Jung Il
JI
Gwak
Mi Sook
MS
Hahm
Tae Soo
TS
D000085:Acetates / Q000008:administration & dosage / Q000494:pharmacology*; D000588:Amines; D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D003509:Cyclohexanecarboxylic Acids; D004305:Dose-Response Relationship, Drug; D000077206:Gabapentin; D007278:Injections, Spinal; D008026:Ligation; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013127:Spinal Nerves / Q000293:injuries*; D013997:Time Factors; D005680:gamma-Aminobutyric Acid
D000085:Acetates; D000588:Amines; D000700:Analgesics; D003509:Cyclohexanecarboxylic Acids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin