The dissociation of heroin-seeking patterns induced by contextual, discriminative, or discrete conditioned cues in a model of relapse to heroin in rats.
BACKGROUND
The role of heroin-related stimuli in motivating the resumption of heroin use is not fully understood.


OBJECTIVE
The objective was to characterize the relative importance of drug-related contextual stimuli, discriminative stimuli (DS), or discrete conditioned stimuli (CSs) on drug seeking when rats were reintroduced into the operant context after withdrawal.


METHODS
Nose-poke responding by male rats was reinforced with intravenous heroin (0.05 mg/kg per infusion, 4-h session daily) under a progressive ratio schedule of reinforcement for 14 days. Each session began with the illumination of a green light in the active hole that served as DS. Each earned heroin injection was paired with a 5-s compound cue light and the sound of the infusion pump that served as the discrete CSs.


RESULTS
Response rates of heroin seeking induced by the contextual stimuli were comparable to the average rates of responding during self-administration training, but rates induced by either DS or CSs were greater than those induced by the contextual stimuli alone (P<0.05). The responding induced by contingent presentations of CSs was higher than that of DS after extinction of instrumental behavior. The drug seeking induced by CSs can be maintained after 3 days extinction with DS in the original context, although the responding elicited by DS cannot be recovered after 3 days of extinction with CSs.


CONCLUSIONS
The relapse to drug seeking can be elicited separately by environmental cues, heroin-predictive DS, or discrete CSs in the same rat after withdrawal.
Zhou
Wenhua
W
Laboratory of Behavioral Neuroscience, Ningbo Addiction Research and Treatment Center, People's Republic of China. whzhou@vip.163.com
Zhang
Fuqiang
F
Tang
Shuaien
S
Liu
Huifen
H
Gu
Jun
J
Yang
Guodong
G
D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D003463:Cues; D004195:Disease Models, Animal; D005108:Extinction, Psychological / Q000187:drug effects; D003932:Heroin / Q000008:administration & dosage / Q000494:pharmacology; D006556:Heroin Dependence / Q000503:physiopathology* / Q000523:psychology; D007262:Infusions, Intravenous; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012008:Recurrence; D012055:Reinforcement Schedule; D012646:Self Administration; D017603:Signal Detection, Psychological; D013375:Substance Withdrawal Syndrome / Q000503:physiopathology / Q000523:psychology; D013997:Time Factors
D000701:Analgesics, Opioid; D003932:Heroin