Receptors responsive to extracellular pyrimidine nucleotides.

Extracellular adenine nucleotides have long been known to mediate pharmacological responses via several subtypes of P2 purinoceptors. More recently, however, similar responses to uracil nucleotides have been demonstrated. Here, Didier Communi and Jean-Marie Boeynaems discuss the evidence to suggest that distinct pyrimidinoceptors do indeed exist, although they do not appear to constitute a separate receptor family of their own.