Retrieval of spatial information in nijmegen high and low responders: Involvement of beta-adrenergic mechanisms in the nucleus accumbens

Rats selected on the basis of their apomorphine susceptibility or on the ba sis of their response to novelty were used to investigate the role of mesol imbic adrenoceptors in the retrieval of spatial information in the water ma ze task. Apomorphine-susceptible rats and high responders to novelty (HR) s howed a relatively bad retrieval during the ist trial of the 2nd day compar ed with apemorphine-unsusceptible mrs and low responders to novelty (LR). I ntra-accumbens injections of different doses of the beta -agonist isoproter enol, given just before that trial, disrupted the retrieval in LR rats but not in HR rats. The beta -antagonist propranolol, which itself did not have any direct effect, inhibited the effect of isoproterenol in LR rats. The e ffect of isoproterenol in LR rats was not modified by a-agents. It is concl uded that the beta -adrenergic, but not cu-adrenergic, activity in the nucl eus accumbens directs the individual-specific ability to retrieve spatial i nformation under stressful conditions.