Biomedical subjects
Publications and source records attributed to L E Carrell.
Zinc (Zn) deficiency is shown to condition aversion to the Zn-deficient diet. After development of a Zn deficiency syndrome during which consumption of the deficient diet decreased, rats readily consumed a familiar Zn-normal diet. After Zn repletion, the previously deficient animals continued to avoid the Zn-deficient diet. These results would not be predicted by the competing hypothesis that Zn-deficiency is anorexigenic.
Ethanol (EtOH) oral self-administration studies using rats have had inconsistent outcomes: studies in which rats are fluid deprived report decreasing EtOH intake over trials, whereas studies not employing fluid deprivation report increasing intake over trials. The present study supports the hypothesis that differential taste aversion learning may account for some of this discrepancy. This study indicates that taste aversion learning is maximized under fluid deprivation conditions and that "latent inhibition," i.e., exposure to non-intoxicating amounts of the EtOH solution prior to conditioning, reduces taste aversion learning. It is suggested that the effect of fluid deprivation on taste aversion resulting from EtOH self-administration may be at least in part due to the development of latent inhibition in non-deprived animals during initial exposure to the EtOH solution.
Taste aversion learning was investigated in two inbred strains of rats known to differ in amount of ethanol (EtOH) they will self-administer orally. The "low EtOH preference" strain, WKYs, acquired an aversion to an EtOH solution during self-administration; but a "high preference" strain, M520s, did not. It was shown that a lower dose of EtOH will condition saccharin aversion in WKYs than in M520s, suggesting EtOH is a more effective US in the low preference strain. Analysis of patterns of EtOH self-administration indicates the pattern of the low preference strain is more likely to result in taste aversion learning. The implications of these results for the presumed relation between EtOH preference and other EtOH-related phenotypes is discussed.
The development of taste aversions was studied in 34 oncology patients undergoing radiotherapy. A target flavor was paired with irradiation on four consecutive treatment days. Self-reported nausea on treatment days reliably predicted aversion learning. The implications of this finding for the anorexia of cancer patients and the role of nausea in human taste aversion learning are discussed.
Six experiments with rats investigated the conditions under which one flavor interferes with aversion conditioning to a second, familiar flavor. Conditioning to the familiar flavor was weakest when the interference flavor was contiguous to lithium-induced toxicosis, novel, more intense, and strongly associated with toxicosis. In addition, conditioning to the familiar flavor was weakened even if multiple conditioning trials were used. The repeated finding of an inverse relationship between strength of aversion to the target and interference flavors is interpreted as support for an associative competition hypothesis of the interference effect. The possible relevance of the interference effect to the attenuation of taste aversions in cancer patients is discussed.