The effects of home-cage access to a sweet solution on the discriminative stimulus effects of cocaine.
This study assessed whether access to a sweet solution in the home cage could change sensitivity to cocaine, using a drug discrimination procedure. Rats were trained to discriminate 10 mg/kg cocaine from saline. After acquisition, rats were tested with a cumulative dose-response procedure (0-18 mg/kg) for 12 consecutive days. The 12 test days consisted of three 4-day cycles. The first cycle obtained a baseline of responding. During the second cycle, rats were given access to a bottle containing either a glucose/saccharin solution (G+S) or distilled water (dH2O) in addition to having free access to water in their home cage. During the final cycle, the G+S or dH2O bottle was removed. Discriminative control in the first cycle did not differ between pre-G+S and pre-dH2O. When the second bottle was presented, median effective dose values (ED50s) for cocaine in animals with access to G+S were higher than baseline, whereas the ED50s for cocaine in animals that received dH2O remained unchanged. During the final cycle when G+S was removed, ED50 values again did not differ after dH2O but remained increased for the rats with previous access to the G+S solution. Our data suggest that rats were less sensitive to the cocaine cue when a sweet solution was available in the home cage.
Kohut
Stephen J
SJ
Psychopharmacology Laboratory, American University, Washington DC, USA. steve.kohut@gmail.com
Riley
Anthony L
AL
D000704:Analysis of Variance; D000779:Anesthetics, Local / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D003042:Cocaine / Q000008:administration & dosage / Q000494:pharmacology*; D003216:Conditioning, Operant / Q000187:drug effects; D004193:Discrimination Learning / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D008297:Male; D051381:Rats; D020318:Rats, Long-Evans; D012439:Saccharin / Q000008:administration & dosage / Q000494:pharmacology*; D012646:Self Administration / Q000379:methods; D013549:Sweetening Agents / Q000008:administration & dosage / Q000494:pharmacology*; D013649:Taste / Q000187:drug effects
D000779:Anesthetics, Local; D013549:Sweetening Agents; D012439:Saccharin; D003042:Cocaine