Stimulation and blockade of α1 adrenoceptors affect behavioural activity,but not spatial working memory assessed by delayed non-matching to position task in rats

Abstract

The present study investigated the role of α₁ adrenergic receptors in the modulation of working memory and behavioural activity by assessing the effects of α₁ adrenergic receptor stimulation or blockade on the performance of rats in a delayed non-matching to position task. St-587 (a putative agonist of α ₁ adrenoceptors) at a dose of 100 μg/kg slightly increased choice accuracy (per cent correct responses) of rats, but the effect was delay-independent which is interpreted as an improvement in choice accuracy and non-mnemonic (non-working memory) in character. Neither St-587 (300 or 1000 μg/kg) nor prazosin (a prototype antagonist of α₁ adrenoceptors) (100 or 300 μg/kg) significantly affected the choice accuracy of rats in this task. Prazosin 300 μg/kg lengthened the latency for correct responses in the working memory task but did not affect food collection latencies. This combination of effects may reflect decreased motor output. St-587 300 and 1000 μg/ kg, but not prazosin, increased food collection latencies in the working memory task. Thus, the present results suggest that α ₁ adrenergic receptors do not play any important role in spatial working memory as assessed using the delayed non-matching to position task, but that modulation of α₁ adrenoceptors may affect motor activity and motivation in rats.