Increased measures of anxiety and weight gain in mice lacking the group III metabotropic glutamate receptor mGluR8

Robert M. Duvoisin, Connie Zhang, Timothy F. Pfankuch, Heather O'Connor, Jacqueline Gayet-Primo, Salma Quraishi, Jacob Raber

Research output: Contribution to journalArticlepeer-review

80 Scopus citations


To study the role of the metabotropic glutamate receptor 8 (mGluR8), mice lacking this receptor were generated by homologous recombination. Homozygous mGluR8-deficient mice are about 8% heavier than their wild-type age-matched controls after reaching 4 weeks of age. This weight difference is not caused by an altered food intake and is not exacerbated by feeding the animals a high-fat diet. Moreover, mGluR8-/- mice are mildly insulin resistant, possibly as a result of being overweight. Behavioral testing revealed a reduced locomotor activity of mGluR8-/- mice compared with wild-type mice during the first 3 days in a novel enclosed environment. However after 3 days, the locomotor activities of wild-type and mGluR8-/- mice were similar, suggesting a reduced exploratory behavior of mGluR8-/- mice in a novel enclosed environment. By contrast, there were no genotype differences in locomotor activity in the open field, plus maze, or in total time spent exploring objects during object recognition tests, indicating that there is a dissociation between effects of mGluR8 deficiency in exploratory activity in a novel safe enclosed environment vs. a more anxiogenic novel open environment. The absence of mGluR8 also leads to increased measures of anxiety in the open field and elevated plus maze. Whether the diverse phenotypic differences observed in mGluR8-/- mice result from the misregulation of a unique neural pathway, possibly in the thalamus or hypothalamus, or whether they are the consequence of multiple developmental and functional alterations in synaptic transmission, remains to be determined.

Original languageEnglish (US)
Pages (from-to)425-436
Number of pages12
JournalEuropean Journal of Neuroscience
Issue number2
StatePublished - Jul 2005


  • Diabetes
  • G protein-coupled receptor
  • Knockout mouse
  • Locomotor activity

ASJC Scopus subject areas

  • General Neuroscience


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