Korean J Anesthesiol.  2007 Dec;53(6):767-773. 10.4097/kjae.2007.53.6.767.

Comparison of Antiallodynic Effects between Intrathecal Cholinesterase Inhibitors and NMDA Antagonists on Two Neuropathic Pain Rat Models

• Kang KN
• Cho SJ
• Hwang JH

• KMID: 1937346
• DOI: http://doi.org/10.4097/kjae.2007.53.6.767

Abstract

BACKGOUND: Cholinesterase inhibitors and N-methyl-D-aspartate (NMDA) antagonists reduce the mechanical allodynia in neuropathic pain models. In this study our aim was to compare the antiallodynic effects between intrathecal cholinesterase inhibitors and NMDA antagonists on two well-characterized neuropathic pain rat models.
METHODS
Male Sprague Dawley rats were anesthetized and either had the left L5 and L6 spinal nerves ligated (SNL group) or Freund complete adjuvant (FCA) administrated to the sciatic nerve (FCA group) in order to cause neuropathic pain. A catheter was implanted into the intrathecal space for drug administration. After obtaining baseline values, edrophonium (3-100microgram), neostigmine (0.3-10microgram), AP-5 (0.3-3microgram) and MK-801 (1-30microgram) were administered intrathecally to each group. The allodynic left hind paw withdrawal thresholds to von Frey hairs were assessed and converted to % MPE. Antiallodynic effects on the two groups were compared by analyzing dose-response curves and ED 50 values. Motor weakness was also checked.
RESULTS
Intrathecal edrophonium, neostigmine, AP-5 and MK-801 had a dose-dependent antiallodynic effect on the two neuropathic pain models. Comparing the antiallodynic effect dose response curves, intrathecal cholinesterase inhibitors had lower ED 50 with steep slopes in the SNL model, whereas intrathecal NMDA antagonists had lower ED 50 in the FCA model, but there were no statistically significant differences between the two models.
CONCLUSIONS
Intrathecal cholinesterase inhibitors and NMDA antagonists have relatively better antiallodynic effects on the SNL and FCA neuropathic pain rat models, respectively.

Keyword

allodynia; cholinesterase inhibitor; Freund complete adjuvant; intrathecal administration; NMDA antagonists,spinal nerve ligation

MeSH Terms

Animals
Catheters
Cholinesterase Inhibitors*
Cholinesterases*
Dizocilpine Maleate
Edrophonium
Hair
Humans
Hyperalgesia
Male
Models, Animal*
N-Methylaspartate*
Neostigmine
Neuralgia*
Rats*
Rats, Sprague-Dawley
Sciatic Nerve
Spinal Nerves
Cholinesterase Inhibitors
Cholinesterases
Dizocilpine Maleate
Edrophonium
N-Methylaspartate
Neostigmine