The effects of response operandum and prior food training on intravenous nicotine self-administration in rats.
Psychopharmacology. 2010-05-01; 211(1): 43-54
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1. Psychopharmacology (Berl). 2010 Jul;211(1):43-54. doi: 10.1007/s00213-010-1866-z.
Epub 2010 May 1.
The effects of response operandum and prior food training on intravenous nicotine
self-administration in rats.
Clemens KJ(1), Caillé S, Cador M.
(1)CNRS UMR 5227, Team “Neuropsychopharmacology of Addiction”, University of
Bordeaux 2, Bordeaux, France.
RATIONALE: Nicotine intravenous self-administration (IVSA) in rats has been
conducted using a variety of methodological procedures with equally variable
OBJECTIVES: Here, we addressed the importance of the type of response operandum
and prior instrumental training with a natural reinforcer on nicotine IVSA and
METHODS: Rats were tested for spontaneous acquisition of IVSA using either nose
poke (NP) or lever press (LVR) operandum. A dose-response test was then
conducted, followed by extinction and cue- and nicotine-induced reinstatement.
RESULTS: The use of the NP operandum resulted in markedly higher levels of IVSA
across acquisition and across dose-response testing compared with the LVR group.
Whereas both groups reinstated following a nicotine prime, only the LVR group
demonstrated cue-induced reinstatement. As a positive control, the experiment was
repeated with cocaine as the reinforcer: equivalent levels of IVSA were observed
across all tests, irrespective of operandum. When rats self-administering
nicotine received instrumental training with a sucrose reinforcer prior to IVSA,
a facilitated acquisition of IVSA was observed in both LVR and NP groups to a
similar extent (the effect of operandum remained), but had little effect on
responding thereafter. During reinstatement testing, both groups now displayed
cue- and nicotine-induced reinstatement, but this was also evident in saline
control animals that had never received nicotine.
CONCLUSIONS: These results suggest that, unlike cocaine, an increased physical
response requirement can decrease nicotine intake. It also indicates that
operandum and prior sucrose training may influence the role that visual cues play
in nicotine dependence.
PMID: 20437028 [Indexed for MEDLINE]