. "\"Combining with a purine or purine derivative (purine nucleoside or purine nucleotide) and transmitting the signal from one side of the membrane to the other to initiate a change in cell activity. A nucleotide is a compound that consists of a nucleoside esterified with a phosphate molecule.\" [GOC:bf, GOC:BHF, GOC:signaling, PMID:9755289]" . . "purinergic receptor activity" . "purinoceptor" . "purinoreceptor" . .