| Abstract No.: | A-B1026 |
| Country: | USA |
| | |
| Title: | BAD HABITS: METHAMPHETAMINE SENSITIZATION ALTERS INSTRUMENTAL PERFORMANCE AND STRIATAL PROTEINS IN RATS |
| | |
| Authors/Affiliations: | 1 Robert Brown*; 1 Weidong Li; 1 Sean Ostlund; 1 Bernard Balleine;
1 University of California at Los Angeles, CA, USA
|
| | |
| Content: | Objectives: We test whether decision making behaviour, that is normally dependent on the dorsal striatum, is affected by the sensitization treatment, and further examine brain tissue for methamphetamine-induced alterations using Western blot.
Materials and Methods: Adult rats were exposed to 30 days of methamphetamine treatment in an escalating dose regime that ranged from 1-6 mg/kg. Following a 30 day recovery period animals were divided into short and long training groups and received different amounts of instrumental training that consisted of learning to press a lever for a food reward. Following acquisition, behaviour was probed in a number of tests after which brains were harvested for analysis by Western blot and in situ labeling.
Results: All animals acquired the instrumental lever press response normally. When the outcome was devalued via lithium chloride poisoning, methamphetamine animals and the long-trained controls used a habitual strategy and continued to press the lever to initiate pellet delivery in extinction. Short-trained controls used a goal directed strategy and had a much lower rate of lever pressing for the devalued outcome. When animals were tested in punished responding (a pellet was delivered following lever press) overtrained saline animals reverted back to the goal directed strategy while the methamphetamine groups persisted with pressing for the devalued outcome. Western blot analysis of tissue revealed a number of differences, in both structural and physiological markers, between the regions of the dorsal striatum responsible for goal directed and habitual strategies in instrumental responding.
Conclusions: Methamphetamine sensitization treatment alters instrumental responding in rats. Observed differences in protein levels are consistent with altered spine density in dorsal striatum following the sensitization treatment.
|
| | |
| Back |
|
