摘要
Numerous studies have suggested a facilitatory role of the noradrenergic system in attention. Cognitive functions relating to attentive states鈥攁rousal, motivation, behavioral flexibility, and working memory鈥攁re enhanced by norepinephrine release throughout the brain. The present study addresses the role of the adrenergic system on stimulus validity and sustained attention within the auditory system. We聽examined the effects of adrenoceptor stimulation via systemic injection of 伪1 and 伪2-adrenoceptor antagonist and agonist drugs, prazosin (1聽mg/kg), phenylephrine (0.1聽mg/kg), yohimbine (1聽mg/kg), and clonidine (0.0375聽mg/kg), respectively. Our results indicate that 伪1-adrenergic stimulation is ineffective in聽modulating the biological assessment of auditory signal validity in the non-stressed rat, while 伪2-adrenoceptor antagonist and agonist drugs were effective in modulating both accuracy and response latencies in the habituated animal. Remarkably, blockade of 伪2-adrenoceptors significantly improved the animal's ability to correctly reject non-signal events. These findings indicate not only a state dependent noradrenergic component of auditory attentional processing, but a potential therapeutic use for drugs targeting norepinephrine release in neurological disorders ranging from Alzheimer's disease to schizophrenia.