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Role for the Rostromedial Tegmental Nucleus in Signaling the Aversive Properties of Alcohol
Author(s) -
Glover Elizabeth J.,
McDougle Molly J.,
Siegel Griffin S.,
Jhou Thomas C.,
Chandler L. Judson
Publication year - 2016
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/acer.13140
Subject(s) - saccharin , nucleus accumbens , taste aversion , ventral tegmental area , glutamatergic , saline , aversive stimulus , alcohol , lithium chloride , hippocampus , addiction , prefrontal cortex , habenula , neuroscience , medicine , ethanol , endocrinology , pharmacology , anesthesia , psychology , chemistry , taste , central nervous system , glutamate receptor , dopamine , biochemistry , receptor , cognition , dopaminergic , organic chemistry
Background While the rewarding effects of alcohol contribute significantly to its addictive potential, it is becoming increasingly appreciated that alcohol's aversive properties also play an important role in the propensity to drink. Despite this, the neurobiological mechanism for alcohol's aversive actions is not well understood. The rostromedial tegmental nucleus ( RMT g) was recently characterized for its involvement in aversive signaling and has been shown to encode the aversive properties of cocaine, yet its involvement in alcohol's aversive actions have not been elucidated. Methods Adult male and female Long–Evans rats underwent conditioned taste aversion ( CTA ) procedures where exposure to a novel saccharin solution was paired with intraperitoneal administration of saline, lithium chloride (LiCl), or ethanol (Et OH ). Control rats underwent the same paradigm except that drug and saccharin exposure were explicitly unpaired. Saccharin consumption was measured on test day in the absence of drug administration, and rats were sacrificed 90 to 105 minutes following access to saccharin. Brains were subsequently harvested and processed for cF os immunohistochemistry. The number of cF os‐labeled neurons was counted in the RMT g and the lateral habenula ( LH b)—a region that sends prominent glutamatergic input to the RMT g. Results In rats that received paired drug and saccharin exposure, Et OH and LiCl induced significant CTA compared to saline to a similar degree in males and females. Both Et OH ‐ and LiCl‐induced CTA significantly enhanced cF os expression in the RMT g and LH b but not the hippocampus. Similar to behavioral measures, no significant effect of sex on CTA ‐induced cF os expression was observed. cF os expression in both the RMT g and LH b was significantly correlated with CTA magnitude with greater cF os being associated with more pronounced CTA . In addition, cF os expression in the RMT g was positively correlated with LHb cF os. Conclusions These data suggest that the RMT g and LH b are involved in the expression of CTA and are consistent with previous work implicating the RMT g in aversive signaling. Furthermore, increased cF os expression in the RMT g following Et OH ‐induced CTA suggests that this region plays a role in signaling alcohol's aversive properties.