Chronic cocaine administration typically results in increased locomotor activity, known as behavioral sensitization. Investigating the time course of locomotor activity across trials may provide a more detailed analysis of the temporal changes that might occur within sensitization. Prior research with rodents shows that the peak of locomotor activity shifts from acute to chronic drug administration. The purpose of the current experiment was to investigate acute versus chronic cocaine effects on locomotor activity in an avian species, Japanese quail, and to investigate whether this phenomenon is dose-dependent. Subjects received daily ip injections of saline or 5, 10, or 20 mg/kg cocaine for 20 days. Following each injection, birds were placed in standard locomotor activity chambers, and activity was recorded for 150 min. A cocaine challenge was given after a ten-day withdrawal period. Two retraining trials were given to re-establish cocaine responding prior to a saline challenge in the drug-paired environment. Results showed that repeated administration of the 10 mg/kg dose of cocaine enhanced activity across 120 min compared with acute administration. In contrast, repeated administration of the 20 mg/kg dose resulted in greater cocaine-induced activity for 60 min compared with acute administration. In addition, behavioral sensitization was shown to be dose-dependent and appeared to be due, at least in part, to conditioning.
|Number of pages||7|
|Journal||Physiology and Behavior|
|State||Published - Apr 23 2007|
Bibliographical noteFunding Information:
The authors gratefully acknowledge Robert Prather, Brad Presley, and Shiraz Yazdani for help with data collection. This research was supported by USPHS grant K01-DA00508 (awarded to C.K. Akins) and a Research Challenge Trust Fund fellowship by the University of Kentucky (awarded to E.H. Geary). We would also like to thank NIDA for providing the cocaine used in this experiment.
- Behavioral sensitization
- Contextual conditioning
- Dose-dependent effect
- Temporal effects
ASJC Scopus subject areas
- Experimental and Cognitive Psychology
- Behavioral Neuroscience