TY - JOUR
T1 - Baclofen, raclopride, and naltrexone differentially reduce solid fat emulsion intake under limited access conditions
AU - Rao, R. E.
AU - Wojnicki, F. H.E.
AU - Coupland, J.
AU - Ghosh, S.
AU - Corwin, R. L.W.
N1 - Funding Information:
Funding for this project provided by the National Institutes of Health (1-R01 MH6794301) (RLC). Additional financial support graciously provided by the Schreyer Honor's College 2006 Summer Research Scholarship. Developmental emulsion product generously donated by Tic Gums™.
PY - 2008/6
Y1 - 2008/6
N2 - Previous work in rats has demonstrated that an Intermittent (Monday, Wednesday, Friday) schedule of access promotes binge-type consumption of 100% vegetable shortening during a 1-h period of availability. The present study used novel shortening-derived stable solid emulsions of various fat concentrations. These emulsions were the consistency of pudding and did not demonstrate oil and water phase separation previously reported with oil-based liquid emulsions. Male Sprague-Dawley rats were grouped according to schedule of access (Daily or Intermittent) to one of three concentrations (18%, 32%, 56%) of solid fat emulsion. There were no significant Intermittent vs. Daily differences in amount consumed, due to high intakes in all groups. This indicated the acceptability of the emulsions. Baclofen (GABAB agonist) and raclopride (D2-like antagonist) both significantly reduced emulsion intake in all Daily groups, but only in the 56% fat Intermittent group. Naltrexone (opioid antagonist), in contrast, significantly reduced 32% and 56% fat emulsion intake in the Intermittent, as well as the Daily groups. These results indicate that the fat intake-reducing effects of GABAB activation and D2 blockade depend upon fat concentration and schedule of fat access, while the fat intake-reducing effects of opioid blockade depend upon fat concentration but not schedule of access.
AB - Previous work in rats has demonstrated that an Intermittent (Monday, Wednesday, Friday) schedule of access promotes binge-type consumption of 100% vegetable shortening during a 1-h period of availability. The present study used novel shortening-derived stable solid emulsions of various fat concentrations. These emulsions were the consistency of pudding and did not demonstrate oil and water phase separation previously reported with oil-based liquid emulsions. Male Sprague-Dawley rats were grouped according to schedule of access (Daily or Intermittent) to one of three concentrations (18%, 32%, 56%) of solid fat emulsion. There were no significant Intermittent vs. Daily differences in amount consumed, due to high intakes in all groups. This indicated the acceptability of the emulsions. Baclofen (GABAB agonist) and raclopride (D2-like antagonist) both significantly reduced emulsion intake in all Daily groups, but only in the 56% fat Intermittent group. Naltrexone (opioid antagonist), in contrast, significantly reduced 32% and 56% fat emulsion intake in the Intermittent, as well as the Daily groups. These results indicate that the fat intake-reducing effects of GABAB activation and D2 blockade depend upon fat concentration and schedule of fat access, while the fat intake-reducing effects of opioid blockade depend upon fat concentration but not schedule of access.
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U2 - 10.1016/j.pbb.2008.02.013
DO - 10.1016/j.pbb.2008.02.013
M3 - Article
C2 - 18353432
AN - SCOPUS:41949102699
SN - 0091-3057
VL - 89
SP - 581
EP - 590
JO - Pharmacology Biochemistry and Behavior
JF - Pharmacology Biochemistry and Behavior
IS - 4
ER -