Purinoceptors in the Nervous System*

Abstract

Abstract:The purine nucleoside adenosine and the purine nucleotide ATP play different roles in the nervous system. Adenosine acts on a family of G protein coupled receptors, collectively called adenosine receptors or P 1 purinoceptors. Four members of this family have been cloned and pharmacologically characterized: A 1 A 2a, A 2b and A 3. Their distribution, pharmacology and biological roles are briefly discussed. In particular, the evidence that adenosine acting at A 1 receptors regulates the release of several neurotransmitters and that adenosine acting at A 2a receptors modulates dopaminergic transmission is summarized. ATP acts on receptors called P 2 purinoceptors, which appear to fall into at least two main families – G protein coupled receptors and intrinsic ion channels. Their subclassification is becoming clearer as receptors are cloned and new selective agonists and/or antagonists are becoming available. There is an interesting potential for development of drugs targeted at purines or their receptors.