title: Metabotropic glutamate 5 receptors regulate sensitivity to ethanol in mice.
abstract: The metabotropic glutamate receptor 5 (mGlu5) has been implicated in ethanol- and drug-seeking behaviours in rodent studies. Here we examine a number of ethanol-related behavioural assays in mice lacking mGlu5 and wild-type littermates. In a two-bottle free-choice paradigm, mGlu5-deficient mice consumed less ethanol with a reduced preference compared to wild-type mice. Indeed, mGlu5-deficienct mice were ethanol-avoiding at both concentrations of ethanol proffered (5% and 10% v/v). However, there was no difference in the rate of hepatic ethanol and acetaldehyde metabolism between genotypes and consumption of saccharin was similar. In a conditioned place preference study, mGlu5-deficient mice displayed a place preference for ethanol when conditioned with a low dose (1g/kg) of ethanol. Thus, while mGlu5-deficient mice consume less ethanol (with a reduced preference) than wild-type mice, this is not apparently related to impaired hepatic metabolism or a lack of reward from ethanol. Rather, we provide evidence that deletion of the mGlu5 receptor increases sensitivity to centrally mediated effects of ethanol.
authors.affiliation: Howard Florey Institute, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: Michael K
authors.initials: MK
authors.lastname: Bird
authors.forename: Jeppe
authors.initials: J
authors.lastname: Kirchhoff
authors.forename: Elvan
authors.initials: E
authors.lastname: Djouma
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Lawrence
mesh_terms: D000426:Alcohol Dehydrogenase / Q000378:metabolism; D000444:Aldehyde Dehydrogenase / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology*; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D002755:Choice Behavior / Q000187:drug effects; D003216:Conditioning, Operant / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate / Q000172:deficiency / Q000502:physiology*; D012018:Reflex / Q000187:drug effects / Q000235:genetics
chemical_list: D002492:Central Nervous System Depressants; D064529:Receptor, Metabotropic Glutamate 5; D018094:Receptors, Metabotropic Glutamate; D000431:Ethanol; D000426:Alcohol Dehydrogenase; D000444:Aldehyde Dehydrogenase