Interaction between caffeine and the dopaminergic system

Acute caffeine administration potentiates dopaminergic transmission in rats, whereas its chronic assumption depresses motor activation induced by dopamine agonists. In order to study if the effects of amphetamine were influenced by intermittent caffeine pretreatment, locomotion and rotational behavior were evaluated in intact and unilaterally 6-hydroxydopamine lesioned rats, previously exposed to caffeine (15 mg/kg on alternate days for 2 weeks). Amphetamine (0.5 and 2 mg/kg) induced a higher rate of locomotion and ipsilateral turning behavior in caffeine- than in vehicle-pretreated rats. In uiuo microdialysis of amphetamine-induced dopamine release, performed in intact striaturn of 6-hydroxydopamine lesioned rats, showed no differences between caffeine- and vehicle-pretreated animals. These results indicate that caffeinepretreatment, facilitating dopamine transmission at postsynaptic level, potentiates the effects of amphetamine