Behavioral and neurochemical characterization of alpha(2A)-adrenergic receptor knockout mice

J Lähdesmäki, J Sallinen, E MacDonald, B K Kobilka, V Fagerholm, M Scheinin

Research output: Contribution to journalArticleScientificpeer-review

95 Citations (Scopus)


Genetic manipulation of mice now provides new tools to evaluate the biological functions of the alpha(2)-adrenergic receptor (alpha(2)-AR) subtypes (alpha(2A), alpha(2B), and alpha(2C)). To investigate the role of the alpha(2A)-AR in the modulation of mouse primary behavioral characteristics and brain neurochemistry, mice with targeted inactivation of the gene for the alpha(2A)-AR were compared with wild-type C57BL/6 control animals. First, a comprehensive behavioral screen was employed to provide a detailed characterization of basic neurologic functions. Thereafter, the mice were analyzed in three models of anxiety, i.e. the elevated-plus maze test, the marble burying test and the open field test. The diurnal activity pattern of the mice was assessed in a 24-h locomotor activity test. Furthermore, receptor autoradiography of the brain was performed using the subtype-non-selective alpha(2)-AR antagonist radioligand [(3)H]RS-79948-197. Lack of the alpha(2A)-AR was associated with alterations in autonomic functions, including increased heart rate and piloerection. The mutant mice also exhibited impaired motor coordination skills, increased anxiety-like behavior and an abnormal diurnal activity pattern. In addition, neurochemical analysis of monoamine neurotransmitters revealed a considerable increase in brain norepinephrine turnover in mice lacking alpha(2A)-AR. Our results provide further support for the crucial role of the alpha(2A)-AR in modulating brain noradrenergic neurotransmission and many aspects of mouse behavior and physiology.

Original languageEnglish
Pages (from-to)289-99
Number of pages11
Issue number2
Publication statusPublished - 2002
MoE publication typeA1 Journal article-refereed


  • Animals
  • Autoradiography
  • Behavior, Animal/physiology
  • Biogenic Monoamines/metabolism
  • Brain/metabolism
  • Male
  • Maze Learning/physiology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout/genetics
  • Motor Activity/physiology
  • Receptors, Adrenergic, alpha/deficiency


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