It is well known that beta-adrenoceptors (beta-ARs) play a critical role in emotional arousal and stressful events, but the specific contributions of the beta 2-AR subtype to the psychological disorders are largely unknown. To investigate whether beta 2-AR are involved in anxiety-like behavior and reward to addictive drugs, we conducted a series of behavioral tests on beta 2-AR knock-out (KO) mice. beta 2-AR KO mice exhibited increased preference for the dark compartment and closed arm in tests of Light/Dark box and elevated plus maze, indicating that beta 2-AR deletion elevates level of anxiety or innate fear. beta 2-AR KO mice also showed decreased immobility in tail suspension test (TST), suggesting that beta 2-AR deletion inhibits depression-like behavior. Interestingly, beta 2-AR ablation did not change basal locomotion but significantly increased locomotor activity induced by acute cocaine administration. beta 2-AR KO mice showed enhanced place preference for cocaine, which could be attenuated by b 1-selective AR antagonist betaxolol. Consistently, beta 2-AR agonist suppressed cocaine-conditioned place preference (CPP). These data indicate that beta 2-AR deletion enhances acute response and reward to cocaine. Our results suggest that beta 2-AR regulates anxiety level, depression-like behavior and hedonic properties of cocaine, implicating that beta 2-AR are the potential targets for the treatment of emotional disorders and cocaine addiction.
[1]Fudan Univ, Collaborat Innovat Ctr Brain Sci, Sch Basic Med Sci, State Key Lab Med Neurobiol, Shanghai, Peoples R China.
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