CHRONIC FOOD-DEPRIVATION DECREASES EXTRACELLULAR DOPAMINE IN THE NUCLEUS-ACCUMBENS - IMPLICATIONS FOR A POSSIBLE NEUROCHEMICAL LINK BETWEENWEIGHT-LOSS AND DRUG-ABUSE

In rats reduced to 80% of normal body weight (n = 9),the basal levels of extracellular dopamine (DA) in the nucleus accumbens (NAC), as dete rmined by microdialysis, decreased significantly to 33% (mean +/- SEM) of their normal baseline (p < .01), Basal extracellular DA did not ch ange significantly over a matching 3-week period in controls (n = 7), No changes were observed in NAC serotonin after weight reduction, Thes e results indicate that parts of the mesolimbic DA system are depresse d in underweight rats, The observed decrease in basal DA may be respon sible for a variety of behavioral changes observed in undernourished h umans and animals including the tendency to eat and gain weight when f ood becomes available, Given that DA can be released in the NAC when r ats self-inject drugs of abuse, the present findings may help explain why animals increase drug intake when they are underweight.