Dopamine antagonists alter response allocation but do not suppress appetite for food in rats: contrast between the effects of SKF 83566, raclopride, and fenfluramine on a concurrent choice task.
BACKGROUND
Dopamine is important for enabling organisms to overcome work-related response costs. One way of investigating this function has been with concurrent choice procedures using food reinforcement. In the present study, rats were given a choice between pressing a lever for preferred Bioserve pellets, or approaching and consuming a less-preferred laboratory chow that was concurrently available. In previous work with this task, dopamine antagonists and accumbens dopamine depletions decreased lever pressing but increased chow consumption.


OBJECTIVE
The present study assessed three drugs (two dopamine antagonists and one appetite suppressant) using the lever pressing/chow feeding task.


RESULTS
Under baseline conditions, rats pressed the lever at high rates (1,300-1,500 responses) to obtain the preferred food, and little of the laboratory chow was eaten (1-2 g). Selective D1 and D2 antagonists (SKF 83566 and raclopride) reduced fixed ratio 5 lever pressing, but substantially increased chow consumption. In contrast, the serotonergic appetite suppressant fenfluramine reduced both lever pressing and chow consumption. With the dopamine antagonists, lever pressing and chow consumption were inversely correlated across treatments, while these two measures were unrelated in the fenfluramine experiment.


CONCLUSIONS
Dopamine antagonists and accumbens dopamine depletions do not simply reduce appetite. Rats with accumbens dopamine depletions, or rats treated with low doses of selective or non-selective dopamine antagonists, remain directed toward the acquisition and consumption of food. These results demonstrate that fundamental aspects of food reinforcement are left intact after treatment with low doses of dopamine antagonists.
Salamone
J D
JD
Department of Psychology, University of Connecticut, Storrs, CT 06269-1020, USA. john.salamone@UConn.edu
Arizzi
M N
MN
Sandoval
M D
MD
Cervone
K M
KM
Aberman
J E
JE
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000818:Animals; D001067:Appetite Depressants / Q000494:pharmacology*; D002755:Choice Behavior / Q000187:drug effects* / Q000502:physiology; D018492:Dopamine Antagonists / Q000494:pharmacology*; D004435:Eating / Q000187:drug effects* / Q000502:physiology; D005277:Fenfluramine / Q000494:pharmacology*; D005518:Food Preferences / Q000187:drug effects / Q000502:physiology; D008297:Male; D020891:Raclopride / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time / Q000187:drug effects* / Q000502:physiology; D012054:Reinforcement, Psychology; D017367:Selective Serotonin Reuptake Inhibitors / Q000494:pharmacology
D015647:2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine; D001067:Appetite Depressants; D018492:Dopamine Antagonists; D005277:Fenfluramine; D020891:Raclopride; D017367:Selective Serotonin Reuptake Inhibitors; C044846:SKF83566