Idazoxan, an alpha-2 antagonist, facilitates memory retrieval in the rat

The role of the noradrenergic system in cognitive function was studied by using the alpha-2 adrenoceptor antagonist idazoxan to increase noradrenergic activity. Rats were trained in a complex maze task for food reward. They were left undisturbed for a 4-week "forgetting" period and were treated with idazoxan, just before the retention test. The dose of idazoxan used had previously been shown to enhance firing of units of the locus coeruleus and to increase noradrenaline (NE) turnover in the forebrain. This pharmacological treatment effectively alleviated forgetting, while control rats showed significant decrement compared to their performance at the last training trial. A control experiment showed that the facilitative effect was not on learning or on ongoing performance of the task, since there was no effect on simple acquisition. The results are taken as support for the notion that NE plays a role in memory retrieval processes.