title: Functional Dissociation of Group III Metabotropic Glutamate Receptors Revealed by Direct Comparison between the Behavioral Profiles of Knockout Mouse Lines.
abstract: BACKGROUND
  Group III metabotropic glutamate receptors (mGlu4, mGlu7, mGlu8) display differential brain distribution, which suggests different behavioral functions. However, comparison across the available animal studies remains methodologically hazardous and controversial. The present report directly compares knockouts for each group III receptor subtype using a single behavioral test battery and multivariate analysis.
  
  
  METHODS
  The behavioral phenotypes of C57BL/6J mice lacking mGlu4, mGlu7, or mGlu8 and their respective littermates were examined using a multimetric test battery, which included elements of neuromotor performance, exploratory behavior, and learning and memory. Multivariate statistical methods were used to identify subtype-specific behavioral profiles and variables that distinguished between these mouse lines.
  
  
  RESULTS
  It generally appears that mGlu7 plays a significant role in hippocampus-dependent spatial learning and in some fear-related behaviors, whereas mGlu4 is most clearly involved in startle and motivational processes. Excepting its influence on body weight, the effect of mGlu8 deletion on behavior appears more subtle than that of the other group III receptors. These receptors have been proposed as potential drug targets for a variety of psychopathological conditions.
  
  
  CONCLUSIONS
  On the basis of these controlled comparisons, we presently conclude that the different group III receptors indeed have quite distinct behavioral functions.
authors.affiliation: KU Leuven, Laboratory of Biological Psychology, Leuven, Belgium (Drs Goddyn, Callaerts-Vegh, and D'Hooge).
authors.forename: Hannelore
authors.initials: H
authors.lastname: Goddyn
authors.affiliation: KU Leuven, Laboratory of Biological Psychology, Leuven, Belgium (Drs Goddyn, Callaerts-Vegh, and D'Hooge).
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Callaerts-Vegh
authors.affiliation: KU Leuven, Laboratory of Biological Psychology, Leuven, Belgium (Drs Goddyn, Callaerts-Vegh, and D'Hooge). rudi.dhooge@ppw.kuleuven.be.
authors.forename: Rudi
authors.initials: R
authors.lastname: D'Hooge
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000502:physiology; D005106:Exploratory Behavior / Q000502:physiology; D005239:Fear / Q000502:physiology; D005260:Female; D007858:Learning / Q000502:physiology*; D008568:Memory / Q000502:physiology*; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009042:Motivation / Q000235:genetics / Q000502:physiology; D009043:Motor Activity / Q000235:genetics / Q000502:physiology*; D015999:Multivariate Analysis; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics / Q000378:metabolism*; D013216:Reflex, Startle / Q000235:genetics / Q000502:physiology
chemical_list: D018094:Receptors, Metabotropic Glutamate; C102719:metabotropic glutamate receptor 7; C111435:metabotropic glutamate receptor 8; C108823:metabotropic glutamate receptor 4
keywords: Metabotropic glutamate receptors; behavioral phenotyping; behavioral test battery; knockout mice