TY - JOUR
T1 - Bilateral lesions of the gustatory thalamus disrupt morphine- but not LiCl-induced intake suppression in rats
T2 - Evidence against the conditioned taste aversion hypothesis
AU - Grigson, Patricia Sue
AU - Lyuboslavsky, Polina
AU - Tanase, Diana
N1 - Funding Information:
This research was supported by U.S. Public Health Service Grants DA 09815 and DC 02016. We thank the National Institute on Drug Abuse for generously providing the morphine sulfate, Ralph Norgren for his contribution to the histological analyses, and Han Li and Kathy Smith for technical support. We also express our appreciation to Steve Reilly, Robert Twining, and Robert Wheeler for reading a version of the manuscript and to Robert Twining and Sarah Ballard for contributing to the statistical analyses.
PY - 2000/3/10
Y1 - 2000/3/10
N2 - Rats decrease intake of a saccharin conditioned stimulus (CS) when followed by: (1) the administration of an aversive agent such as lithium chloride (referred to as a conditioned taste aversion, CTA); (2) access to a very palatable concentration of sucrose (referred to as an anticipatory contrast effect, ACE); or (3) the administration of a drug of abuse. It is not clear, however, whether the suppressive effects of drugs of abuse are mediated by their aversive or rewarding properties. The present set of experiments addressed this issue by examining the suppressive effects of morphine in rats with a lesion thought to dissociate the two phenomena (i.e., CTA and ACE). The results show that bilateral ibotenic acid lesions of the gustatory thalamus eliminate the suppressive effects of morphine, but fail to disrupt the suppressive effects of the aversive agent, lithium chloride. This pattern of results argues against the CTA account in favor of the reward comparison hypothesis. Specifically, the data suggest that rats suppress intake of a saccharin CS in anticipation of the availability of a preferred drug of abuse and that the gustatory thalamus is essential for this type of reward comparison process. Copyright (C) 2000 Elsevier Science B.V.
AB - Rats decrease intake of a saccharin conditioned stimulus (CS) when followed by: (1) the administration of an aversive agent such as lithium chloride (referred to as a conditioned taste aversion, CTA); (2) access to a very palatable concentration of sucrose (referred to as an anticipatory contrast effect, ACE); or (3) the administration of a drug of abuse. It is not clear, however, whether the suppressive effects of drugs of abuse are mediated by their aversive or rewarding properties. The present set of experiments addressed this issue by examining the suppressive effects of morphine in rats with a lesion thought to dissociate the two phenomena (i.e., CTA and ACE). The results show that bilateral ibotenic acid lesions of the gustatory thalamus eliminate the suppressive effects of morphine, but fail to disrupt the suppressive effects of the aversive agent, lithium chloride. This pattern of results argues against the CTA account in favor of the reward comparison hypothesis. Specifically, the data suggest that rats suppress intake of a saccharin CS in anticipation of the availability of a preferred drug of abuse and that the gustatory thalamus is essential for this type of reward comparison process. Copyright (C) 2000 Elsevier Science B.V.
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U2 - 10.1016/S0006-8993(00)01939-9
DO - 10.1016/S0006-8993(00)01939-9
M3 - Article
C2 - 10708684
AN - SCOPUS:0034628977
SN - 0006-8993
VL - 858
SP - 327
EP - 337
JO - Brain research
JF - Brain research
IS - 2
ER -