LITHIUM CHLORIDE-INDUCED ANOREXIA, BUT NOT CONDITIONED TASTE-AVERSIONS, IN RATS WITH AREA POSTREMA LESIONS

Area postrema (AP) lesions were produced by vacuum aspiration in adult male Sprague-Dawley rats. Consistent with previous findings, when water-deprived rats were allowed to drink novel flavored fluids immediately before treatment with LiCl (3 mEq/kg, i.p.), sham-operated and non-operated control rats demonstrated a pronounced aversion to the fluids whereas rats with AP lesions did not decrease fluid consumption significantly. However, in a 30-min test period after overnight food deprivation, rats with AP lesions reduced food intake significantly and to an equivalent degree as control animals when pretreated with LiCl (3 mEq/kg, i.p. or i.v.). These and other results are consistent with the traditional view that AP mediates the sensation of nausea produced by LiCl treatment (hence the loss of conditioned taste aversions after AP lesions), but suggest that neither nausea nor AP is necessary for the marked disinclination to eat that is induced in rats by acute administration of LiCl.