alpha(2)- and beta-adrenoceptors involvement in nortriptyline modulation of auditory sustained attention and impulsivity

作者：Roychowdhury Swagata; Pena Contreras Zulma; Tam Jason; Yadlapalli Amulya; Dinh Lu; Nichols Justin Andrew; Basu Debarshi; Atzori Marco^*

来源：Psychopharmacology, 2012, 222(2): 237-245.

DOI：10.1007/s00213-012-2635-y

• Norepinephrine
• Nortriptyline
• Auditory
• Sustained attention
• Impulsivity
• Response latency
• Rat
• Operant chamber
• Alpha-2 adrenoceptors
• Beta adrenoceptors

The catecholamine innervation of the prefrontal cortex controls attentional focus and inhibits inappropriate behavioral responses. The mechanism of action with which norepinephrine (NE) reuptake inhibitors modulate these cognitive functions has not been fully investigated. %26lt;br%26gt;We investigated the effect of systemic administration of the NE reuptake blocker nortriptyline (NT) on attention and impulsivity using an auditory sustained attention task. The task was designed to assess impulsive behavior and the maintenance of attentional focus to an auditory stimulus presented at interresponse time durations (IRT) between 5 and 80 s. %26lt;br%26gt;NT (2.0 but not 3.0 mg/kg) improved sustained attention and decreased the percentage of premature responses without changing their latency. To better understand the adrenergic component of NT action, we tested the effect of noradrenergic receptor antagonists alone or together with NT. The alpha(2)-receptor antagonist yohimbine, the alpha(1)-receptor antagonist prazosin, or the beta-receptor antagonist propranolol alone did not significantly affect attentive performance or premature responses. However, the beneficial effects of NT on sustained attention and premature responses were attenuated by pretreatment with either yohimbine or propranolol. On the contrary, prazosin did not affect the NT-mediated improvement in sustained attention. %26lt;br%26gt;We conclude that sustained attention displays an inverse U-shaped dependence on NT, mediated-at least in part-by alpha(2)- and beta-adrenoceptors. We speculate that low doses of NT improve performance by maximizing the phasic release of NE, while higher doses of NT would elevate tonic levels of NE, thus producing suboptimal levels of phasically released NE.

• 出版日期2012-7