Chronic treatment with the potential antidepressant drug rolipram: the effect on the behavioural responses to adrenergic and dopaminergic receptor agonists with some biochemical correlates

Summary We studied the effect of acute and chronic treatment with rolipram, a potential antidepressant drug, on the behavioural responses induced by adrenergic and dopaminergic receptor agonists in mice and rats, and on (³H)prazosin and (³H)dihydroalprenolol binding to cortical membranes and whole brain noradrenaline and dopamine utilization in rats. Chronic, but not acute, administration of rolipram potentiated a behavioural response mediated through central₁-adrenoceptors, attenuated an₂-adrenoceptormediated response and inhibited a-adrenoceptor-mediated response. Neither treatment affected the behavioural responses to dopaminergic stimulants. Repeated treatment with rolipram decreased the density of cortical (³H)dihydroalprenolol, but not (³H)prazosin bindings sites, and reduced brain noradrenaline, but not dopamine utilization. These results suggest that chronic administration of rolipram induces the down-regulation of the central- and₂-adrenoceptors and enhances the responsiveness of the central₁-adrenoceptors with no apparent changes in the₁-adrenoceptor density.