Antiparkinsonian effects of novel adenosine A(2A) receptor antagonists.

The present work describes the synthesis of a pyrazinopurinedione derivative which was together with a series of pyrimidopurinedione derivatives tested for potential antiparkinsonian activity in two tests: the "oxotremorine" and the "reserpine" test. For the studies compounds which had shown affinity for the adenosine A(2A) receptor were chosen. One compound, a pyrazinopurinedione derivative, without affinity for A(2A) receptors, but showing adenosine A(1) receptor affinity was also investigated. The performed preliminary tests indicated that, contrary to the pyrazinopurinedione all pyrimidopurinediones demonstrated antiparkinsonian effects. As a result of present studies it may be concluded that antiparkinsonian effects of the examined compounds are correlated with the antagonistic activity toward adenosine A(2A) receptors in this class of compounds. However a direct correlation of the potency of both effects was not observed possibly due to different pharmacokinetic properties of the compounds. The most active derivatives of the present series were aryl-substituted pyrimidopurinediones.