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Published on: January 6, 2011
Naltrexone prevents footshock-induced performance deficit in rats
Life Sciences
|May 21, 1984
Summary
Inescapable stress in rats causes pain relief and learning deficits, both reversed by the opiate antagonist naltrexone. This suggests these effects involve the brain's opioid system.
Area of Science:
- Neuroscience
- Behavioral Psychology
- Pharmacology
Background:
- Stress-induced analgesia is a known phenomenon.
- Opioid receptors play a crucial role in pain modulation.
- Behavioral deficits following stress require further investigation into their underlying mechanisms.
Purpose of the Study:
- To investigate the effects of inescapable footshock on pain perception and learning in rats.
- To determine the role of opioid receptors in stress-induced analgesia and performance deficits.
- To examine the pharmacodynamics of naltrexone in reversing these effects.
Main Methods:
- Rats were subjected to inescapable footshock.
- Pain response was measured using antinociceptive assays.
- Learning and memory were assessed through one-way shuttle avoidance task.
- Rats were pretreated with varying doses of naltrexone, an opiate antagonist.
Main Results:
- Inescapable footshock induced significant analgesia (pain reduction).
- Footshock also led to deficits in one-way shuttle acquisition (learning impairment).
- Pretreatment with naltrexone (0.1 mg/kg i.p.) completely blocked both the analgesic and performance deficits.
- The results indicate a dose-dependent effect of naltrexone.
Conclusions:
- Stress-induced analgesia and performance deficits in rats are mediated by the endogenous opioid system.
- Opioid receptors are critically involved in both the pain-relieving and learning-impairing effects of inescapable stress.
- Naltrexone's efficacy suggests similar naltrexone pharmacodynamics underlie both observed effects.
