Stimulation and blockade of alpha(1) adrenoceptors affect behavioural activity, but not spatial working memory assessed by delayed non-matching to position task in rats

The present study investigated the role of alpha(1) adrenergic receptors in the modulation of working memory and behavioural activity by assessing the effects of alpha(1) adrenergic receptor stimulation or blockade on the performance of rats in a delayed non-matching to position task. St-587 (a putative agonist of alpha(1) adrenoceptors) at a dose of 100 mu g/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 mu g/kg) nor prazosin (a prototype antagonist of alpha(1) adrenoceptors) (100 or 300 mu g/kg) significantly affected the choice accuracy of rats in this task. Prazosin 300 mu g/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 mu g/kg, but not prazosin, increased food collection latencies in the working memory task. Thus, the present results suggest that alpha(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 alpha 1 adrenoceptors may affect motor activity and motivation in rats.