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Uncontrollable stress potentiates morphine's rewarding properties
M J Will1, L R Watkins, S F Maier
1Department of Psychology, University of Colorado at Boulder, 80309-0345, USA.
Pharmacology, Biochemistry, and Behavior
|July 25, 1998
Summary
Acute stress, particularly uncontrollable stress, enhances the rewarding effects of morphine, increasing drug preference. This effect is temporary and specific to certain drugs, highlighting stressor controllability as a key factor in addiction vulnerability.
Area of Science:
- Neuroscience
- Psychology
- Pharmacology
Background:
- Stress is a significant factor in the development and maintenance of drug addiction.
- Understanding how stressors influence the rewarding properties of drugs is crucial for addiction research.
Purpose of the Study:
- To investigate the impact of an acute stressor, specifically inescapable tail shock, on morphine-induced conditioned place preference.
- To determine the temporal dynamics and specificity of stressor-induced potentiation of drug reward.
Main Methods:
- Subjects received either inescapable tail shock or home-cage control treatment.
- Morphine (0-3 mg/kg) was administered for conditioning 24 hours after stressor exposure.
- Conditioned place preference was assessed, and locomotion was monitored.
- The effects of an anxiogenic drug (DMCM) and escapable shock were also examined.
Main Results:
- Inescapable shock significantly potentiated morphine-induced conditioned place preference.
- This potentiation persisted for up to 7 days post-stress but diminished by 14-15 days.
- Locomotion and amphetamine place preference were unaffected, indicating specificity.
- The anxiogenic DMCM also potentiated preference, and the effect of shock was dependent on its uncontrollability.
Conclusions:
- Acute, uncontrollable stress enhances the rewarding effects of morphine in a time-limited and drug-specific manner.
- Stressor uncontrollability is a critical element in potentiating drug reward.
- These findings provide insights into the neurobiological mechanisms linking stress and addiction vulnerability.