TY - JOUR
T1 - μ opioid receptor agonist DAMGO-induced suppression of saccharin intake in Lewis and Fischer rats
AU - Liu, Chuang
AU - Sue Grigson, Patricia
N1 - Funding Information:
This research was supported by U.S. Public Health Service Grants DA 09815 and DA 12473 from the National Institute on Drug Abuse. We thank Dr. Michael E. Smith for his technical assistance. Part of the work was presented at the annual meeting of the Society for Neuroscience in 2003.
PY - 2005/12/7
Y1 - 2005/12/7
N2 - Rats suppress intake of a saccharin cue when paired with a drug of abuse such as morphine or cocaine. Relative to Lewis rats, Fischer rats exhibit greater avoidance of a saccharin cue following saccharin-morphine pairings. The present study used the μ agonist, [d-Ala2,N-MePhe 4,Gly-ol5]enkephalin (DAMGO), to test whether strain differences in sensitivity of the μ receptor contribute to this effect. Water-deprived Lewis and Fischer rats were given 5 min access to 0.15% saccharin followed by an icv injection of either DAMGO (0.5 microg/1 microl/rat) or an equal volume of saline. There were six taste-drug pairings occurring at 48 h intervals. The results showed that, relative to the saline treated controls, all rats reduced intake of the saccharin cue following saccharin-DAMGO pairings. No differences occurred between strains. These data suggest that greater morphine-induced suppression of saccharin intake by the Fischer rats is not likely mediated by differences in sensitivity of the μ receptor. Other mechanisms are implicated.
AB - Rats suppress intake of a saccharin cue when paired with a drug of abuse such as morphine or cocaine. Relative to Lewis rats, Fischer rats exhibit greater avoidance of a saccharin cue following saccharin-morphine pairings. The present study used the μ agonist, [d-Ala2,N-MePhe 4,Gly-ol5]enkephalin (DAMGO), to test whether strain differences in sensitivity of the μ receptor contribute to this effect. Water-deprived Lewis and Fischer rats were given 5 min access to 0.15% saccharin followed by an icv injection of either DAMGO (0.5 microg/1 microl/rat) or an equal volume of saline. There were six taste-drug pairings occurring at 48 h intervals. The results showed that, relative to the saline treated controls, all rats reduced intake of the saccharin cue following saccharin-DAMGO pairings. No differences occurred between strains. These data suggest that greater morphine-induced suppression of saccharin intake by the Fischer rats is not likely mediated by differences in sensitivity of the μ receptor. Other mechanisms are implicated.
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U2 - 10.1016/j.brainres.2005.10.005
DO - 10.1016/j.brainres.2005.10.005
M3 - Article
C2 - 16259967
AN - SCOPUS:28844501896
SN - 0006-8993
VL - 1064
SP - 155
EP - 160
JO - Brain research
JF - Brain research
IS - 1-2
ER -