Reduced anxiety-- and depression-like behaviors in Emx1 homozygous mutant mice

Brain Res. 2002 May 24;937(1-2):32-40. doi: 10.1016/s0006-8993(02)02461-7.


Emx1 is a mammalian homolog of the Drosophila gap gene empty spiracles (ems). Although it has been implicated in the formation of the mouse forebrain, the neuronal functions of this homeobox gene remain unknown. The restricted expression of Emx1 to the cerebral cortex and hippocampus suggests that it might play a role in emotional and other behavioral processes. The present study examined the phenotypes of Emx1-deficient mice generated by gene targeting technology in a battery of behavioral tests with a fixed inter-trial interval of 7 days. Compared with their wild-type littermates, the Emx1 homozygous mutant mice displayed markedly lowered anxiety-like behaviors in the elevated plus maze and dark/light exploration tests. Moreover, they exhibited less depressive-like response as indicated by the reduced duration of immobility in the forced swimming paradigm. There was a trend toward reduction in prepulse inhibition of acoustic startle in the homozygotes. No significant alterations in locomotor activity and susceptibility to pentylenetetrazol-induced seizure were found. This behavioral profile indicates an involvement of Emx1 in the emotional responses of mice.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acoustic Stimulation
  • Animals
  • Anxiety / genetics
  • Anxiety / physiopathology*
  • Convulsants / toxicity
  • Depression / genetics
  • Depression / physiopathology*
  • Exploratory Behavior / physiology
  • Female
  • Genetic Predisposition to Disease
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / physiology*
  • Homozygote
  • Ion Channel Gating
  • Male
  • Maze Learning / physiology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Nerve Tissue Proteins / deficiency
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / physiology*
  • Pentylenetetrazole / toxicity
  • Reflex, Startle / genetics
  • Reflex, Startle / physiology
  • Seizures / chemically induced
  • Seizures / genetics
  • Seizures / physiopathology
  • Swimming
  • Transcription Factors


  • Convulsants
  • Homeodomain Proteins
  • Nerve Tissue Proteins
  • Transcription Factors
  • empty spiracles homeobox proteins
  • Pentylenetetrazole