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Effect of substance P on intravenous self-administration of morphine in different rat strains

S K Sudakov1, I B Figurina, O F Medvedeva

  • 1Laboratory of Attraction Neurobiology, Institute of Drug Abuse, Russian Ministry of Health, Moscow. ssudakov@mtu-net.ru

Bulletin of Experimental Biology and Medicine
|January 10, 2002
PubMed

Insights

Substance P treatment significantly reduced morphine self-administration in rats, particularly in those with lower brain substance P levels. This suggests a potential therapeutic target for opioid addiction.

Area of Science:

  • Neuroscience
  • Pharmacology
  • Addiction Research

Background:

  • Opioid addiction remains a significant public health challenge.
  • Substance P is a neuropeptide implicated in various physiological processes, including pain and stress responses.
  • Understanding the role of endogenous neuropeptides in modulating drug-seeking behavior is crucial for developing novel addiction therapies.

Purpose of the Study:

  • To investigate the effects of substance P on intravenous morphine self-administration in WAG/G and Fischer-344 rat strains.
  • To determine if substance P influences motivated behaviors unrelated to drug seeking, such as food procurement.

Main Methods:

  • Intravenous self-administration of morphine was assessed in WAG/G and Fischer-344 rats.
  • Rats were treated with varying doses of substance P.
  • Food-procuring behavior was measured in the same experimental chambers to control for general activity changes.

Main Results:

  • WAG/G rats self-administered higher daily amounts of morphine compared to Fischer-344 rats by week 2.
  • Substance P treatment markedly suppressed morphine self-injection, with more pronounced effects in Fischer-344 rats.
  • Substance P did not alter food-procuring behavior, indicating specificity for drug-seeking actions.
  • Despite lower baseline substance P levels in Fischer-344 rats, which correlated with less pronounced morphine addiction, substance P administration abolished morphine addiction in these animals, especially those with low endogenous levels.

Conclusions:

  • Substance P administration can effectively suppress morphine self-administration in rats.
  • The effectiveness of substance P in abolishing morphine addiction appears particularly significant in individuals with lower endogenous substance P levels.
  • These findings suggest that substance P modulation may represent a novel therapeutic strategy for treating opioid addiction.

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