title: Examinations of the reward comparison hypothesis: The modulation of gender and footshock.
abstract: The reward comparison hypothesis suggests that drugs of abuse-induced conditioned saccharin suppression intake is due to the reward value of drugs of abuse that outweighs that of a saccharin solution dissociating from the aversive LiCl-induced conditioned taste aversion (CTA). Huang and Hsiao (2008) provided some conflict data to challenge the reward comparison hypothesis. Whether the rewarding drugs of abuse-induced conditioned suppression and the aversive LiCl-induced CTA resulted from aversion or reward should be addressed. The present study investigated how gender and footshock affect aversive LiCl- and rewarding morphine- and methamphetamine (MAMPH)-induced conditioned suppression to re-examine the reward comparison hypothesis. The results indicated that gender and footshock did not directly influence the aversive LiCl-induced CTA or rewarding morphine- and MAMPH-induced conditioned suppression. The gender effect interacted with the drug effect in the aversive LiCl- and rewarding MAMPH-induced conditioned suppression but did not interact with the drug effect in the rewarding morphine-induced conditioned suppression. Footshock interacted with the drug effect in rewarding morphine- and MAMPH-induced conditioned suppression, but footshock did not interact with the drug effect in the aversive LiCl-induced CTA. Therefore, the gender and footshock effects might play a modulatory (but not a mediating) role with the drug effect. The present data indicated that footshock modulates drugs of abuse-induced conditioned suppression, which is consistent with the reward comparison hypothesis, but our findings with regard to the modulatory role of the gender effect and the drug effect do not support this hypothesis. The reward comparison hypothesis should be discussed and possibly reconsidered.
authors.affiliation: Department of Psychology, Fo Guang University, Yilan County 26247, Taiwan. Electronic address: chweihuang@mail.fgu.edu.tw.
authors.forename: Andrew Chih Wei
authors.initials: AC
authors.lastname: Huang
authors.affiliation: Department of Psychology, Fo Guang University, Yilan County 26247, Taiwan.
authors.forename: Cheng Chung
authors.initials: CC
authors.lastname: Wang
authors.affiliation: Department of Psychology, Fo Guang University, Yilan County 26247, Taiwan.
authors.forename: Shiun
authors.initials: S
authors.lastname: Wang
mesh_terms: D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D003213:Conditioning, Psychological / Q000187:drug effects* / Q000502:physiology; D004597:Electroshock; D005260:Female; D005528:Foot; D013287:Illicit Drugs / Q000494:pharmacology*; D018021:Lithium Chloride / Q000494:pharmacology; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology; D008960:Models, Psychological; D009020:Morphine / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects / Q000502:physiology; D009294:Narcotics / Q000494:pharmacology; D011619:Psychotropic Drugs / Q000494:pharmacology; D011897:Random Allocation; D017208:Rats, Wistar; D012201:Reward; D012439:Saccharin; D012727:Sex Characteristics
chemical_list: D000697:Central Nervous System Stimulants; D013287:Illicit Drugs; D009294:Narcotics; D011619:Psychotropic Drugs; D008694:Methamphetamine; D009020:Morphine; D012439:Saccharin; D018021:Lithium Chloride
keywords: Conditioned taste aversion; Footshock; Gender; LiCl; Methamphetamine; Morphine; Reward comparison hypothesis