The effects of anorectic and aversive agents on deprivation-induced feeding and taste aversion conditioning in rats

We compared the effects of intraperitoneally administered LiCl (0.5-2830 mumol/kg), sulfated cholecystokinin26-33 (10-1000 nmol/kg; CCK-8), nonsulfated CCK-8 (500 and 1000 nmol/kg), sulfated CCK26-29 (500 and 1000 nmol/kg), CCK30-33 (10-1000 nmol/kg) bombesin (10-1000 nmol/kg; BOM), (dl) fenfluramine HCl (0.9-37.3 mumol/kg; fenfluramine), fluoxetine HCl (2.9-86.7 mumol/kg; fluoxetine), and d-amphetamine sulfate (0.27-10.9 mumol/kg; AMPH) on both 18-hr deprivation-induced feeding and one-bottle, taste aversion conditioning in male, Long-Evans rats. Doses of LiCl > or = 177 mumol/kg (or 7.5 mg/kg) induced significant, dose-related taste aversions, but only doses of LiCl > or = 2123 mumol/kg (90 and 120 mg/kg) induced significant anorexia. CCK-8 induced marked anorexia (at doses > or = 25-50 nmol/kg), but only relatively mild taste aversions which were only statistically significant at the highest dose (1000 nmol/kg). The anorectic effects of CCK-8 at 500 and 1000 nmol/kg, but not at lower doses, lasted at least 3 hr. Sulfated CCK26-29, CCK30-33 and nonsulfated CCK-8 induced neither anorexia nor taste aversion. BOM induced marked anorexia at all doses tested, but did not induce statistically significant taste aversions. The nonpeptidal anorectic compounds, fenfluramine, fluoxetine, and AMPH, induced both dose-related anorexia and taste aversion conditioning. We focus on several issues concerning the interpretation of taste aversion conditioning. Our results challenge any simple relationship between the ability of a compound to induce taste aversion and to decrease feeding.