Rationale: Intermittent footshock stress effectively reinstates extinguishe
d heroin-, cocaine- and alcohol-taking behaviors, but not behaviors previou
sly maintained by food reinforcers. Here we tested further the generality o
f the phenomenon of stress-induced reinstatement by determining the effect
of footshock on reinstatement of operant responding previously maintained b
y nicotine or palatable sucrose solutions. Methods: Groups of rats were tra
ined to self-administer either nicotine (0.03 mg/kg per infusion, 14 days)
or sucrose (10 or 30% w/v, 14-20 days). After extinction of the nicotine- o
r the sucrose-reinforced behaviors for 5-15 days, the rats were exposed to
intermittent footshock stress (5 and 15 min, 0.8 mA) during tests for reins
tatement. Results: Footshock reliably reinstated nicotine seeking after ext
inction of the drug-reinforced behavior. In contrast, the same parameters o
f footshock stress did not consistently reinstate operant responding previo
usly maintained by sucrose solutions. Conclusions: These and previous data
suggest that stressors may be more effective stimuli for reinstatement of b
ehaviors previously maintained by drug reinforcers as compared with non-dru
g reinforcers.