Antagonism of adenosine A2A receptors underlies the behavioural activating effect of caffeine and is associated with reduced expression of messenger RNA for NGFI-A and NGFI-B in caudate–putamen and nucleus accumbens

摘要: Abstract Caffeine, the most widely consumed of all psychostimulant drugs, exerts its action by antagonizing adenosine receptors. To study arousing properties caffeine, we injected rats intraperitoneally with vehicle, caffeine (7.5, 15 or 30 mg/kg), selective A2A receptor antagonist, SCH 58261 (3.75 mg/kg) A1 antagonist DPCPX (7.5 mg/kg). In a behavioural test it was found that administration and significantly increased locomotion rearing, whereas did not alter reduced rearing. After session were killed, their brains cut at several levels along rostrocaudal axis in situ hybridization against NGFI-A messenger RNA NGFI-B performed. A reduction subregions both caudate–putamen nucleus accumbens caffeine-treated animals. Similarly, animals had received showed significant decreases rostral part shell accumbens. By contrast, treatment caused an increase expression smaller lateral parts caudate–putamen. addition, but DPCPX, elevated cerebral cortex, especially parietal part. Thus, these results provide evidence endogenous adenosine, via receptors, causes tonic activation striatopallidal neurons. blocking this effect, activation.