The NMDA-receptor antagonist ketamine as an unconditioned stimulus in taste aversion learning.
Three experiments studied the effectiveness of ketamine acting as an aversive unconditioned stimulus (UCS) in a conditioned flavor aversion procedure. In Experiment 1a, three conditioning trials where sucrose was paired with ketamine produced a weak but significant aversion to sucrose; Experiment 1b showed that this effect was not due to a reduced consumption of sucrose caused by ketamine-induced neophobia. In Experiment 2, acquisition of an aversion to sucrose paired with lithium chloride (LiCl) injections was retarded by prior repeated exposure to LiCl but not to ketamine. These results are not consistent with an interpretation of previous results, showing that ketamine impairs the acquisition of flavor aversions based on LiCl-induced illness, as an example of the UCS preexposure effect.
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Facultad de Psicología, Universidad Complutense, Madrid, Spain. psbas17@sis.ucm.es
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D000818:Animals; D001245:Association Learning / Q000187:drug effects* / Q000502:physiology; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D001921:Brain / Q000187:drug effects / Q000502:physiology; D003214:Conditioning, Classical / Q000187:drug effects* / Q000502:physiology; D019422:Dietary Sucrose / Q000008:administration & dosage; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D007649:Ketamine / Q000494:pharmacology*; D018021:Lithium Chloride / Q000494:pharmacology; D008297:Male; D011939:Mental Recall / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors* / Q000502:physiology; D013649:Taste / Q000187:drug effects* / Q000502:physiology
D019422:Dietary Sucrose; D018691:Excitatory Amino Acid Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D007649:Ketamine; D018021:Lithium Chloride