Related Experiment Videos
Apomorphine sensitization effects: evidence for environmentally contingent behavioral reorganization processes
1Research and Development Service, VA Medical Center, Syracuse, NY.
Pharmacology, Biochemistry, and Behavior
|July 1, 1993
Summary
Repeated apomorphine administration in rats led to behavioral reorganization, not just sensitization. This study suggests a new framework for understanding drug-environment interactions and behavioral changes from psychostimulant treatments.
Area of Science:
- Neuroscience
- Behavioral Pharmacology
- Animal Behavior
Background:
- Behavioral sensitization is a key phenomenon in psychostimulant drug research.
- Understanding the precise mechanisms of behavioral changes induced by drugs like apomorphine is crucial.
Purpose of the Study:
- To investigate apomorphine-induced behavioral sensitization using a Pavlovian conditioning paradigm.
- To re-evaluate the concept of behavioral sensitization in light of observed behavioral dynamics.
Main Methods:
- Rats received daily subcutaneous injections of apomorphine (2.0 mg/kg) for 7 days.
- A Pavlovian conditioning paradigm paired or unpaired drug administration with environment exposure.
- Video-image analysis quantified angular movement and locomotion patterns.
Main Results:
- Apomorphine initially caused hypolocomotion, which shifted to hyperlocomotion by day 5.
- Increased locomotion was attributed to enhanced wide-angle rotation, not increased rotation frequency.
- A stable, directional rotation bias emerged, independent of initial asymmetry.
Conclusions:
- The study proposes 'behavioral reorganization' as an alternative to 'behavioral sensitization'.
- This new framework better explains the progressive, structured behavioral changes observed with repeated dopaminergic psychostimulant treatment.
- Behavioral reorganization highlights the interactive role of the drug and environment in shaping behavior.