Incubation of sucrose craving: effects of reduced training and sucrose pre-loading.
Time-dependent increases in cue-induced reward seeking after forced abstinence were described in rats with a history of cocaine or sucrose self-administration, suggesting reward craving incubates over time. In the present study, we examined the effects of reduced training experience, or sucrose pre-loading just prior to testing, on the incubation of sucrose craving. Sucrose seeking (responding in extinction and then for a sucrose-paired cue) increased over time in groups of rats that self-administered sucrose 6 h/day for 10 days and were tested at 1, 7, or 30 days of forced abstinence. We found that groups of rats that had self-administered 2 instead of 6 h/day showed a similar profile of responding. Incubation of sucrose craving was attenuated by free access to sucrose in home cages for 17 h immediately prior to testing assessed as extinction responding on days 1 and 30. However, this sucrose pre-loading had no effect on the time-dependent increase in responding for the sucrose-paired cue. In summary, reducing the training experience had no effect on the incubation of sucrose craving and free access to sucrose had only a limited effect-attenuating extinction responding. These results illustrate the strength of the incubation of craving and further suggest long-term changes in brain motivational circuitry following sucrose self-administration.
Grimm
Jeffrey W
JW
Department of Psychology, Western Washington University, 516 High Street, Bellingham, WA 98225-9089, USA. jeff.grimm@wwu.edu
Fyall
Amber M
AM
Osincup
Dan P
DP
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal; D003216:Conditioning, Operant / Q000187:drug effects* / Q000502:physiology; D003463:Cues; D005108:Extinction, Psychological / Q000187:drug effects* / Q000502:physiology; D005793:Generalization, Psychological; D008297:Male; D051381:Rats; D020318:Rats, Long-Evans; D012646:Self Administration; D013375:Substance Withdrawal Syndrome / Q000523:psychology*; D013395:Sucrose / Q000008:administration & dosage*; D013997:Time Factors
D013395:Sucrose