Emotional response in dopamine D2L receptor-deficient mice

Behav Brain Res. 2008 Dec 22;195(2):246-50. doi: 10.1016/j.bbr.2008.09.007. Epub 2008 Sep 18.


The dopamine D2 receptor (D2R) system has been implicated in emotional processing which is often impaired in neuropsychiatric disorders. The long (D2L) and the short (D2S) isoforms of D2R are generated by alternative splicing of the same gene. To study differential roles of the two D2R isoforms, D2L-deficient mice (D2L-/-) expressing functional D2S were previously generated. In this study the contribution of D2L isoform to emotional response was investigated by examining behaviors that reflect emotionality (exploratory behavior, anxiety-like behavior and learned helplessness) in D2L-/- and (wild-type) WT mice. While the thigmotactic, locomotor and general components of anxiety in zero maze did not differ among the genotypes, D2L-/- mice displayed significantly lower level of exploration in a hole board and zero maze, and significantly higher increase in latency to escape from a foot-shock after the learned helplessness training, compared with WT mice. These results suggest that D2L may play a more prominent role than D2S in mediating emotional response, such as behavioral reactions to novelty and inescapable stress. Our findings contribute to a better understanding of the molecular and cellular mechanisms underlying emotional responses.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing
  • Analysis of Variance
  • Animals
  • Anxiety / physiopathology
  • Avoidance Learning / physiology
  • Behavior, Animal / physiology*
  • Electroshock / methods
  • Emotions / physiology*
  • Escape Reaction / physiology
  • Exploratory Behavior / physiology
  • Helplessness, Learned
  • Male
  • Maze Learning / physiology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Motor Activity / physiology
  • Protein Isoforms / deficiency
  • Protein Isoforms / genetics
  • Protein Isoforms / physiology
  • Receptors, Dopamine D2 / deficiency*
  • Receptors, Dopamine D2 / genetics
  • Receptors, Dopamine D2 / physiology*


  • Protein Isoforms
  • Receptors, Dopamine D2
  • dopamine D2L receptor