Antinociceptive effect of ambroxol in rats with neuropathic spinal cord injury pain.

Abstract

Symptoms of neuropathic spinal cord injury (SCI) pain include evoked cutaneous hypersensitivity and spontaneous pain, which can be present below the level of the injury. Adverse side-effects obtained with currently available analgesics complicate effective pain management in SCI patients. Voltage-gated Na(+) channels expressed in primary afferent nociceptors have been identified to mediate persistent hyperexcitability in dorsal root ganglia (DRG) neurons, which in part underlies the symptoms of nerve injury-induced pain. Ambroxol has previously demonstrated antinociceptive effects in rat chronic pain models and has also shown to potently block Na(+) channel current in DRG neurons. Ambroxol was tested in rats that underwent a mid-thoracic spinal cord compression injury. Injured rats demonstrated robust hind paw (below-level) heat and mechanical hypersensitivity. Orally administered ambroxol significantly attenuated below-level hypersensitivity at doses that did not affect performance on the rotarod test. Intrathecal injection of ambroxol did not ameliorate below-level hypersensitivity. The current data suggest that ambroxol could be effective for clinical neuropathic SCI pain. Furthermore, the data suggest that peripherally expressed Na(+) channels could lend themselves as targets for the development of pharmacotherapies for SCI pain.

• Authors: Aldric T Hama, Ann Woodhouse Plum, Jacqueline Sagen
• Journal: Pharmacology, biochemistry, and behavior (Pharmacol Biochem Behav) Vol. 97 Issue 2 Pg. 249-55 (Dec 2010) ISSN: 1873-5177 [Electronic] United States
• PMID: 20732348 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2010 Elsevier Inc. All rights reserved.

Chemical References

• Analgesics
• Sodium Channel Blockers
• Ambroxol

Topics

• Ambroxol (pharmacology)
• Analgesics
• Animals
• Behavior, Animal (drug effects)
• Hot Temperature
• Hyperalgesia (drug therapy, psychology)
• Injections, Spinal
• Male
• Motor Activity (drug effects)
• Neuralgia (drug therapy, etiology)
• Pain Measurement (drug effects)
• Pain Threshold (drug effects)
• Physical Stimulation
• Postural Balance (drug effects)
• Rats
• Rats, Sprague-Dawley
• Sodium Channel Blockers (pharmacology)
• Spinal Cord Injuries (complications, drug therapy)