Reversal of a feeding-reward system by dexfenfluramine: neurochemical involvement.
In addition to its anorectic properties, dexfenfluramine may inhibit some manifestations of feeding-related reward. We attempted to verify this effect by measuring paw-lick latency on the hot plate test in rats conditioned to expect a palatable food. The involvement of variations in beta-endorphinergic, dopaminergic and serotonergic systems was assessed. Despite an inherent effect of increasing paw-lick latency, dexfenfluramine (1.5 mg/kg IP) partly reversed the expectancy-induced increase in this latency. Saline-treated "expectant" rats displayed elevated plasma beta-endorphin levels and reduced hypothalamic 5-HIAA/5-HT and DOPAC/DA ratios. Only the decrease in the DOPAC/DA ratio was reversed by dexfenfluramine, suggesting an involvement of the dopaminergic system in this dexfenfluramine-sensitive reward system.
Orosco
M
M
Laboratoire de Pharmacologie, URA-CNRS 594, Faculté de Pharmacie, Chatenay-Malabry, France.
Robert
J J
JJ
Rouch
C
C
Jacquot
C
C
Cohen
Y
Y
D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects*; D001921:Brain / Q000187:drug effects*; D004298:Dopamine / Q000502:physiology*; D005247:Feeding Behavior / Q000187:drug effects*; D005260:Female; D005277:Fenfluramine / Q000494:pharmacology*; D009042:Motivation; D009619:Nociceptors / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012684:Sensory Thresholds / Q000187:drug effects; D012701:Serotonin / Q000502:physiology*; D001615:beta-Endorphin / Q000502:physiology*
D005277:Fenfluramine; D012701:Serotonin; D001615:beta-Endorphin; D004298:Dopamine