Probenecid Sodium

Probenecid Sodium, a benzoic acid derivative, is a classic inhibitor of organic anion transporters (OATs) (Ki = 6.3, 9.0, and 8.4 μM for OAT1, OAT3, and OAT6, respectively; IC50 = 0.67 μM for OAT2); it exhibits very weak inhibitory activity against organic cation transporters OCT1 and OCT2 (IC50 = 1.6 and 1.7 mM). Organic anion transporters are located on the cell membrane and frequently efflux fluorescent probes from the cell, resulting in poor intracellular retention of the probes—a phenomenon that typically leads to high background signals in staining experiments. The use of probenecid inhibits transporter activity, thereby reducing the leakage of intracellular fluorescent probes; this is a commonly employed method for lowering fluorescent background levels in calcium assays. Probenecid acts as an agonist for the transient receptor potential channel protein TRPV2 (EC50 = 31.9 μM) and can induce nociceptive behaviors in mice under inflammatory conditions. Furthermore, probenecid is an inhibitor of the multidrug resistance-associated protein 1 (MRP1); it blocks the MRP1 active site, thereby preventing the efflux of other active compounds and allowing these compounds to be retained within the cytoplasm, which enhances their therapeutic effects. Probenecid also functions as an inhibitor of the gap junction protein Pannexin-1.