title: D1 but not D2 dopamine receptor antagonism blocks the acquisition of a flavor preference conditioned by intragastric carbohydrate infusions.
abstract: The effects of dopamine D1 (SCH23390) and D2 (raclopride) receptor antagonists on the acquisition and expressions of flavor preferences conditioned by the postingestive actions of sucrose were investigated. Food-restricted rats were trained in one-bottle sessions to associate one flavored saccharin solution (CS+) with intragastric (i.g.) infusions of 16% sucrose, and another flavored saccharin solution (CS-) with water infusions. Flavor preferences were then measured in two-bottle tests. In Experiment 1A, rats that received the D2 antagonist (raclopride, 200 nmol/kg; RAC group) throughout training consumed less CS+ and CS- than did saline-treated Control rats; a saline-treated Yoked group had its intake limited to that of the RAC group. All three groups displayed CS+ preferences during two-bottle tests when treated with saline or raclopride, except at doses that greatly suppressed intake. Experiment 1B obtained similar results with rats treated with 400 nmol/kg raclopride throughout training. In Experiment 2, rats that received the D1 antagonist (SCH23390, 200 nmol/kg; SCH group) throughout training consumed less CS+ and CS- than did saline-treated Control rats; a saline-treated Yoked group had its intake limited to that of the SCH group. Unlike the Control and Yoked groups, the SCH group failed to prefer the CS+ to the CS- in two bottle tests. SCH23390 treatment during two-bottle testing did not block CS+ preference in the Control or Yoked groups, except at doses that greatly suppressed intake. We conclude that D1, but not D2, dopamine receptors are critically involved in the acquisition of a sucrose-conditioned flavor preference, and both receptor subtypes have a more limited role in the expression of this preference.
authors.affiliation: Department of Psychology, Brooklyn College of City University of New York, USA.
authors.forename: A V
authors.initials: AV
authors.lastname: Azzara
authors.forename: R J
authors.initials: RJ
authors.lastname: Bodnar
authors.forename: A R
authors.initials: AR
authors.lastname: Delamater
authors.forename: A
authors.initials: A
authors.lastname: Sclafani
mesh_terms: D000818:Animals; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D019422:Dietary Sucrose / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology*; D065127:Dopamine D2 Receptor Antagonists; D004750:Enteral Nutrition / Q000379:methods; D005518:Food Preferences / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors* / Q000502:physiology; D017448:Receptors, Dopamine D2 / Q000502:physiology; D012439:Saccharin / Q000494:pharmacology; D013549:Sweetening Agents / Q000494:pharmacology
chemical_list: D004040:Dietary Carbohydrates; D019422:Dietary Sucrose; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D013549:Sweetening Agents; D012439:Saccharin