Purinoceptors in the nervous system.
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 P1 purinoceptors. Four members of this family have been cloned and pharmacologically characterized: A1, A2A, A2B and A3. Their distribution, pharmacology and biological roles are briefly discussed. In particular, the evidence that adenosine acting at A1 receptors regulates the release of several neurotransmitters and that adenosine acting at A2A receptors modulates dopaminergic transmission is summarized. ATP acts on receptors called P2 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.
Fredholm
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BB
Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
D000241:Adenosine / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D004285:Dogs; D008969:Molecular Sequence Data; D009420:Nervous System / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism; D051381:Rats; D018047:Receptors, Purinergic P1 / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D018048:Receptors, Purinergic P2 / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D015398:Signal Transduction
D018377:Neurotransmitter Agents; D018047:Receptors, Purinergic P1; D018048:Receptors, Purinergic P2; D000255:Adenosine Triphosphate; D000241:Adenosine