Characterization of a dose-response curve for nicotine-induced conditioned taste aversion in rats: relationship to elevation of plasma beta-endorphin concentration

In the first experiment a conditioned taste aversion paradigm was used to characterize a dose-response curve for the aversive properties of nicotine in male Sprague-Dawley rats. Doses of nicotine ranging from 0.01 to 0.46 mg/kg, 2.0 ml of 0.47 M lithium chloride, or saline were injected, ip, 10 min after exposure to a novel saccharin solution. Amount of saccharin consumed in a two-bottle test was assessed 72 h later. Nicotine doses of 0.046 mg/kg and above produced a significant degree of conditioned taste aversion. In a second experiment, four groups of 10 rats each were injected with saline, 0.022 mg/kg nicotine, 0.46 mg/kg nicotine, or 2.0 ml 0.47 of M LiCl. Doses of 0.46 mg/kg nicotine and 0.47 M LiCl elevated plasma beta-endorphin concentrations significantly above saline control values. The 0.022 mg/kg dose, the highest dose that did not produce conditioned taste aversion in Experiment 1, did not significantly increase plasma beta-endorphin concentrations. This finding suggests that doses of nicotine that produce conditioned taste aversion also promote the release of pituitary stress hormones. Taken together these data suggest that some of the pharmacological and behavioral effects attributed to nicotine, including the release of endogenous neuromodulators, may be dose-dependent concomitants of the aversive effects of nicotine in nicotine-naive animals.     

Emotional State,Physical Well-Being,and Performance in the Presence of Feigned Ambient Odor1

Measures of emotional state, physical well-being, performance, and room odor were obtained from subjects given the suggestion of a pleasant, unpleasant, or neutral ambient odor (n= 30 per condition). The hedonic quality of the feigned odor altered self-reports of pleasure, but not dominance or arousal. Subjects given the pleasant suggestion reported a more positive mood. The number of reported physical health symptoms differed as a function of the hedonic quality of the feigned odor. The category corresponding to the fewest number of physical symptoms was predominated by subjects in the pleasant condition, while subjects in the unpleasant condition predominated the category with the greatest number of symptoms. Subjects predicted higher task performance in the unpleasant condition, but no differences were found among conditions in actual performance. Room odor ratings differed in directions consistent with the hedonic quality of the feigned odor. The effects of olfactory suggestion may be relevant to the psychosomatic component of sick building syndrome and to the perception and marketing of fragrance.     

Recall and recognition of self-performed acts

Summary In Experiment 1, recall and recognition of 80 action phrases were compared under two encoding conditions: verbal and motor (performing the denoted acts). Memory performance was better under motor encoding than under verbal encoding, and more so in recognition than in recall. We assume that this finding is due to the item-specific effect of a specific motor component in the memory trace after enacting. In Experiments 2 and 3 we further investigated whether false-alarm rates are dependent on the motoric similarity of distractor items. The rate of false alarms was lower under motor encoding than under verbal encoding, but the motoric similarity of distractor items to list items did not influence the false alarms. The results were interpreted as support for the assumption that motor encoding enhances item-specific information in relation to verbal encoding, but that during verbal recognition the motoric quality of the depicted movement is not processed.