| Abstract
| - The present study explores the C-3‘ site of the3-deoxy-3-xylofuranosyl ring of nucleosideanalogues with an adenine orN6-cyclopentyladenine (CPA) base moiety andevaluates the effecton adenosine receptor affinity. Two series of sugar-modifiedadenosines, i.e., 3‘-amido-3‘-deoxyadenosines and 3‘-amidated 3‘-deoxyxylofuranosyladenines, weresynthesized and testedfor their affinity at A1 and A2a receptors inrat brain cortex and rat striatum, respectively.The modest affinity found in the “xylo series” prompted us tosynthesize the correspondingN6-cyclopentyl derivatives, which proved to bewell accommodated by the A1 receptors withpotencies in the lower nanomolar range. This represents a newperspective in the purinergicfield. The absence of a GTP-induced shift, i.e., the ratio betweenthe affinities measured inthe presence and absence of 1 mM GTP indicates an antagonistic behaviorof this new class ofCPA analogues.
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