Accumbens dopamine mechanisms in sucrose intake.
Extracellular levels of dopamine (DA) and monoamine metabolites were measured in the nucleus accumbens (NAcc) during sucrose licking using microdialysis in freely moving rats. The converse relationship also was tested. Using bilateral reverse microdialysis, D1 and D2 receptor antagonists (SCH23390, sulpiride) and the DA uptake blocker nomifensine were introduced into NAcc while measuring both ingestive behavior and neurochemistry. Licking of 0.3 M sucrose caused a 305% (+/-69%) increase in NAcc DA compared with water intake. Reverse microdialysis of nomifensine at a dose that increased accumbens DA levels (1484+/-346%) led to an increase of sucrose intake (152.5+/-5.4%). Concurrent infusions of the D1 and D2 blockers with nomifensine brought sucrose ingestion back near to control levels (114.8+/-3.7%). The higher dose of the D2 antagonist sulpiride also increased DA levels and sucrose intake. In contrast, the lower dose of the D2, and both doses of the D1 antagonist had no chemical or behavioral effects. These results showed release of NAcc DA in response to sucrose licking and the converse, an augmentation of the behavior by uptake blockade. The same data, however, failed to prove that tonic, local accumbens D1 and D2 receptor activity influenced this ingestive behavior.
Hajnal
A
A
Department of Behavioral Science, H181, College of Medicine, Pennsylvania State University, P.O. Box 850, Hershey, PA 17033, USA. asb40@psu.edu
Norgren
R
R
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D019422:Dietary Sucrose / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D018492:Dopamine Antagonists / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology; D004435:Eating / Q000187:drug effects / Q000502:physiology*; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology*; D006719:Homovanillic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D009627:Nomifensine / Q000494:pharmacology; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors / Q000378:metabolism; D017448:Receptors, Dopamine D2 / Q000378:metabolism; D012201:Reward
D019422:Dietary Sucrose; D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D018765:Dopamine Uptake Inhibitors; D017447:Receptors, Dopamine D1; D017448:Receptors, Dopamine D2; D015102:3,4-Dihydroxyphenylacetic Acid; D009627:Nomifensine; D004298:Dopamine; D006719:Homovanillic Acid