Intraventricular insulin and leptin reverse place preference conditioned with high-fat diet in rats.
The authors hypothesized that insulin and leptin, hormones that convey metabolic and energy balance status to the central nervous system (CNS), decrease the reward value of food, as assessed by conditioned place preference (CPP). CPP to high-fat diet was blocked in ad-lib fed rats given intraventricular insulin or leptin throughout training and test or acutely before the test. Insulin or leptin given only during the training period did not block CPP. Thus, elevated insulin and leptin do not prevent learning a food's reward value, but instead block its retrieval. Food-restricted rats receiving cerebrospinal fluid, insulin, or leptin had comparable CPPs. Results indicate that the CNS roles of insulin and leptin may include processes involving memory and reward.
Figlewicz
Dianne P
DP
Metabolism/Endocrinology (151), Veterans Affairs Puget Sound Health Care System, 1660 South Columbian Way, Seattle, WA 98108, USA. latte@u.washington.edu
Bennett
Jennifer
J
Evans
Scott B
SB
Kaiyala
Karl
K
Sipols
Alfred J
AJ
Benoit
Stephen C
SC
D000818:Animals; D001522:Behavior, Animal; D001835:Body Weight / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects*; D004041:Dietary Fats / Q000494:pharmacology*; D004347:Drug Interactions; D004734:Energy Metabolism; D005508:Food Deprivation; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007276:Injections, Intraventricular; D007328:Insulin / Q000494:pharmacology*; D020738:Leptin / Q000494:pharmacology*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley
D004041:Dietary Fats; D007004:Hypoglycemic Agents; D007328:Insulin; D020738:Leptin