4825
Extracellular purine and pyrimidine nucleotides are involved in the physiology of virtually every body district , and their extracellular concentrations massively increase under pathological situations , suggesting that they might represent potential targets for the modulation of disease - associated symptoms , like pain .
 Chemical: purine and pyrimidine nucleotides
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
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Answer:
 Chemical: purine and pyrimidine nucleotides