Morphine and gabapentin decrease mechanical hyperalgesia and escape/avoidance behavior in a rat model of neuropathic pain

Neurosci Lett. 2000 Aug 25;290(2):137-40. doi: 10.1016/s0304-3940(00)01340-9.


A behavioral test paradigm that measures the aversive quality of stimulus-evoked pain in an animal model of neuropathic pain (L5 ligation) was tested for sensitivity to (1) different forces (476 and 202 mN) and frequencies (once every 15 or 30 s) of mechanical stimulation to the hyperalgesic paw and (2) different doses of the common antinociceptive compounds morphine (1 and 10 mg/kg) and gabapentin (30 and 90 mg/kg). Compared to non-ligated controls, the greater force (476 mN) and frequency (every 15 s) of mechanical stimulation of the hyperalgesic paw was associated with the greatest degree of escape/avoidance behavior. There was not a significant degree of escape/avoidance behavior at the lowest force (202 mN) and frequency (every 30 s) of mechanical stimulation. Compared to ligated vehicle treated controls, morphine (1 mg/kg) and gabapentin (90 mg/kg) decreased mechanical hyperalgesia and also attenuated the escape/avoidance behavior. The antinociceptive and antiaversive effects were found at doses that did not produce evidence of decreased motor activity. It is concluded that the behavioral test paradigm used to measure the aversiveness of stimulus-evoked nociceptive behavior is sensitive to different degrees of evoked pain and traditional analgesic compounds.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / pharmacology*
  • Amines*
  • Analgesics / pharmacology*
  • Animals
  • Avoidance Learning / drug effects*
  • Avoidance Learning / physiology
  • Cyclohexanecarboxylic Acids*
  • Disease Models, Animal
  • Dose-Response Relationship, Drug
  • Gabapentin
  • Hyperalgesia / drug therapy*
  • Hyperalgesia / pathology
  • Hyperalgesia / physiopathology
  • Male
  • Morphine / pharmacology*
  • Nerve Crush / adverse effects*
  • Peripheral Nervous System Diseases / drug therapy*
  • Peripheral Nervous System Diseases / pathology
  • Peripheral Nervous System Diseases / physiopathology
  • Physical Stimulation / adverse effects
  • Physical Stimulation / methods
  • Rats
  • Rats, Sprague-Dawley
  • gamma-Aminobutyric Acid*


  • Acetates
  • Amines
  • Analgesics
  • Cyclohexanecarboxylic Acids
  • gamma-Aminobutyric Acid
  • Gabapentin
  • Morphine