Potent and human GPR35-selective antagonist that effectively blocks agonist-induced cellular responses without significant effect toward rat or mouse GPR35.

CID 2745687 is a potent and human GPR35-selective antagonist that effectively blocks agonist pamoic acid (PA)-induced cellular responses using human HA-GPR35a-expressing U2OS transfectants (Ki = 12.8 or 18 nM against 1 µM PA by βarr2-GFP recruitment and ERK1/2 phosphorylation, respectively), while exhibiting no significant effect toward rat or mouse GPR35. CID 2745687 is competitive against cromolyn disodium and zaprinast, while being noncompetitive against PA.