Chronic lithium chloride infusions: Conditioned suppression of food intake and preference

Developed a modified learned food aversion paradigm that simulated the prolonged food and illness exposure likely to characterize nutrient deficiencies or tumor growth. In this paradigm, a continuously available food was associated with a slow, continuous infusion of LiCl provided by an osmotic minipump. In Exps I and II, 68 rats were implanted with minipumps with LiCl or with empty pumps and exposed to novel or familiar diets. In Exp III, conducted with 40 Ss, the variable was prior exposure to the same diet. Significant aversions were acquired when the available diet was novel but not when it was familiar. Effects of drug infusions on daily food intake paralleled those on aversion formation. Marked, persistent suppression of food intake was seen in drug-treated Ss consuming a novel diet, but only transient declines were seen in those with a familiar diet. By separating the direct from the conditioned effects on food intake of chronic drug infusions, these studies provided strong evidence that learned food aversions can lead to anorexia. (17 ref)