This invention provides a receptor having a preference for pyrimidine nucleotides preferably uridine triphosphate over purine nucleotides. A receptor having a preference for pyrimidine nucleotides over purine nucleotides means a receptor for which pyrimidine nucleotides and purine nucleotides are not equally active and equipotent. This means that the receptor according to the invention in presence of these agonists presents a functional response (preferably the accumulation of Inositol triphosphate (IP3), diacylglycerol (DAG), or calcium ions) to lower concentration of pyrimidine nucleotides, preferably uridine triphosphate, than to purine nucleotides or a more important functional response to similar concentration of pyrimidine nucleotide than to purine nucleotide.